Ia- Electronics Lm Grade 7 & 8 p&d

LEARNING MATERIALS

ELECTRONICS

Table of Contents

Table of Contents I. INTRODUCTION II. OBJECTIVES III. PRE-ASSESSMENT IV. LEARNING GOALS/TARGETS V. COMMON COMPETENCIES A. KNOW Lesson 1. Occupational Health and Safety Lesson 2. Introduction to Electricity Lesson 3. Basic Structure of Matter Lesson 4. Electric Charge Lesson 5. The Valence Shell Lesson 6. Electrical Current Lesson 7. Voltage Lesson 8. Resistance B. PROCESS Lesson 1. OHM’s Law

Lesson 2. Complete Circuit Lesson 3. Types of Circuit Lesson 4. Circuit Diagrams Lesson 5. Resistor Lesson 6. Other Electronic Components Lesson 7. Basic Hand Tools and Equiment C. REFLECT AND UNDERSTAND Lesson 1/Activity 1: Resistor Color Coding Lesson 2/Activity 2: Proper Use of Soldering Iron Lesson 3/Activity 3: Desoldering Lesson 4/Activity 4: How to Use Use and and Read Read a Multimeter Lesson 4/Activity 5: Use the Right Tool for the Job D. TRANSFER Performance 1/Assessment 1: Construction of Series Circuit Performance 2/Assessment 2: Construction of Parallel Circuit Performance 3/Assessment 3: Soldering Technique Using Wire Performance 4/Assessment 4: Soldering Components on PCB Performance 5/Assessment 5: Astable Multivibrator Using Transistor VI. SUMMARY VII. GLOSSARY VIII. REFERENCES TLE-IA CONSUMER ELECTRONICS SERVICING

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Table of Contents I. INTRODUCTION II. OBJECTIVES III. PRE-ASSESSMENT IV. LEARNING GOALS/TARGETS V. COMMON COMPETENCIES A. KNOW Lesson 1. Occupational Health and Safety Lesson 2. Introduction to Electricity Lesson 3. Basic Structure of Matter Lesson 4. Electric Charge Lesson 5. The Valence Shell Lesson 6. Electrical Current Lesson 7. Voltage Lesson 8. Resistance B. PROCESS Lesson 1. OHM’s Law

Lesson 2. Complete Circuit Lesson 3. Types of Circuit Lesson 4. Circuit Diagrams Lesson 5. Resistor Lesson 6. Other Electronic Components Lesson 7. Basic Hand Tools and Equiment C. REFLECT AND UNDERSTAND Lesson 1/Activity 1: Resistor Color Coding Lesson 2/Activity 2: Proper Use of Soldering Iron Lesson 3/Activity 3: Desoldering Lesson 4/Activity 4: How to Use Use and and Read Read a Multimeter Lesson 4/Activity 5: Use the Right Tool for the Job D. TRANSFER Performance 1/Assessment 1: Construction of Series Circuit Performance 2/Assessment 2: Construction of Parallel Circuit Performance 3/Assessment 3: Soldering Technique Using Wire Performance 4/Assessment 4: Soldering Components on PCB Performance 5/Assessment 5: Astable Multivibrator Using Transistor VI. SUMMARY VII. GLOSSARY VIII. REFERENCES TLE-IA CONSUMER ELECTRONICS SERVICING

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I. INTRODUCTION Your Technology & Livelihood Education (TLE) subject has four areas: Information and Communication Technoloy (ICT), Home Economics (HE), AgriFishery Arts (AFA) and Industrial Arts (IA). Consumer Electronics is a course under Industrial Arts.

Electronics is a branch of physics that deals with the behavior and controlled flow of electrons. Have you ever been curious about what is inside an FM radio box? Will you be able to identify the components present inside that box? So many small components inside that box. The voltage commonly used in home appliances is 220V (It varies from country to country). 220 V is applied between the terminals of the primary coil of transformer. A transformer has the capability to change high voltage to low voltage and vice versa. It converts 220 V into low level voltage. If you explore inside a computer, you will find many rectangular shaped objects which have many vertical pins along the edges. Known as Integrated Circuits Ci rcuits (IC), these chips consist of many electronic components.

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Consumer Electronics Servicing is a full course that leads to the National Certificate Level II (NCII).CES is designed to enhance your knowledge, skills, and attitudes as a trainee/student on core competencies of electronics such as assembly/disassembly of consumer electronic products and systems, maintainance and repair of audio/video products, electronically-controlled domestic appliances and cellular phones in accordance with industry standards. It also includes basic competencies such as, being able to participate in workplace communication, work in team environment, practice career professionalism and practice occupational health and safety procedures. This module will mainly focus on, only common competencies such as: basic hand tools and equipment; maintaining hand tools and equipment; performing mensuration and calculation; preparing and interpreting schematic diagrams; and occupational health and safety will be introduced.

Career Oppurtunities Service technicians are electronic home entertainment equipment installers and repairers; they can repairs a number of different products; among them are televisions and radios, stereo components, video and audio disc players, video cameras, video recorders and cellphones.


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Smaller portable equipment and devices may be brought to repair shops for service by customers. The workers here, called bench or shop technicians, have on hand a wide variety of electronic tools and parts. Customers may request technicians to make house calls when bigger, not so portable equipment breaks down. The workers that typically make house calls are known as field technicians, and carry with them a small set of tools and spare parts in order to make repairs on-site for the customer. When field technicians run into a complicated jobs or problems, they may return to the shop with the faulty part in order to identify the problem and finish the repair there. Growth in consumer electronics servicing as a career is expected to rise steadily because repair is a lot cheaper than buying a new consumer product. Furthermore, job opportunities are widely availlable both locally and abroad to those who are knowledgeable and well experienced in this field .

II. OBJECTIVES At the end of this module, you, as a learner, are expected to: 1. demonstrate understanding of the concepts and underlying principles of process and delivery in using consumer electronics hand tools and equipment while observing occupational and safety practices. III. PRE-ASSESSMENT Direction: Match the different hand tools in column A with their actual pictures in column B. Write the letter on the blank provided before each number. A ____1.Soldering iron

A.

____2.Desoldering tool

B.

____3.Soldering stand

C.

____4. Long nose pliers

D.


B

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____5.Mini- drill

E.

____6.Paint brush

F.

____7. Blade cutter

G.

____8. Side-cutter

H.

____9. Wire splicer

I.

____10. Magnifying glass

J.

K.

IV. LEARNING GOALS/TARGETS:

Now that you have an idea of the coverage of this module, set your learning goal in terms of what you want to attain at the end of your lessons in Consumer Electronics Servicing. Next, specify this in terms of the following: Goal:

____________________________________________

Targets: a. What I want to know: _________________________ b. What I want to be able to do: ___________________ c. What I want to understand: _____________________ d. What I want to produce or understand: _____________ Start writing your own learning goals/targets on your notebook based on the stated objectives. TLE-IA CONSUMER ELECTRONICS SERVICING

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V. COMMON COMPETENCIES A. KNOW Lesson 1. Occupational Health and Safety (OHS) After reading this section you will be able to do the following:  

Define occupational health and safety. Value the importance of health and safety at work.

Occupational safety and health (OSH) is a crossdisciplinary area concerned with protecting the safety, health and welfare of people engaged in work or employment. The goals of occupational safety and health programs include fostering a safe and healthy work environment. OSH may also protect co-workers, family members, employers, customers, and many others who might be affected by the workplace environment.

Occupational safety and health are important for moral, legal, and financial reasons. Moral obligations involve the protection of employee's lives and health. Legal reasons for OSH practices relate to the preventive, punitive, and compensatory effects of laws that protect worker's safety and health. OSH can also reduce employee injury and illness related costs, including medical care, sick leave and disability benefit costs. OSH may involve interactions among many subject areas, including occupational medicine, occupational hygiene, public health, safety engineering, industrial engineering, chemistry, health physics, ergonomics, and occupational health psychology. TLE-IA CONSUMER ELECTRONICS SERVICING

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WORKSHOP SAFETY RULES In any activity involving skills, it is a standard procedure to always use the right tool or equipment properly in a particular task. In spite of this reminder or caution, some students abuse the use of some tools and still commit errors that may cause accidents. Below are safety rules to be observed in the workplace. 1. Always listen carefully to the teacher and follow instructions. 2. Do not run in the workshop, you could ‘bump’ into another student and cause an accident. 3. Know where the emergency stop buttons/power switches are positioned in the workshop. If you see an accident at the other side of the workshop you can use the emergency stop button/power switches to turn off all electrical power to machines. 4. Always wear an apron as it will protect your clothes and hold lo ose clothing. 5. Wear good strong shoes. 6. When attempting practical work all stools should be put away. 7. Bags should not be brought into a workshop as people can trip over them. 8. When learning how to use a tool/machine, listen very carefully to all the instructions given by the teacher. Ask questions, especially if you do not fully understand the given instruction. 9. Do not use a tool/machine if you have not been shown how to operate it safely by the teacher. 10. Always be patient, never rush in the workshop. 11. Keep hands away from moving/rotating machinery. 12. Use hand tools carefully, keeping both hands behind the cutting edge. 13. Report any damage to tools, machines & equipment as this could cause an accident. Suggested Activities: For additional localized information regarding Occupational Health and Safety please download the NATIONAL PROFILE ON OCCUPATIONAL SAFETY AND HEALTH (PHILIPPINES) from http://www.oshc.dole.gov.ph or by using this shortcut link: http://cloud.eacomm.com/oshc2010/UserFiles/oshc2010/file/National-OSHProfile.pdf. The teacher may require the students to visit the following interactive sites. TLE-IA CONSUMER ELECTRONICS SERVICING

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Safety Check Safety Check is an online Occupational Health and Safety (OHS) test designed for workers. Use this test to learn more about topics such as OHS laws; manual handling; hazardous substances; noise; mechanical equipment; and electricity. Link: http://203.147.178.216/safeworksa/EducationAndTraining/ActivitiesAndTests/ SafetyCheck/default.asp Virtual Office Working in the office environment may not be as safe as you think! A test of safety knowledge designed for students and young workers, or workers who may need reminding to be alert for hazards in the workplace. Link: http://www.safework.sa.gov.au/contentPages/EducationAndTraining/Activities AndTests/VirtualOffice/vofficeframe.htm 10 Commandments of Workplace Safety http://www.youtube.com/watch?v=08yxsNnzwnY&feature=related

Question: What is occupational health and safety? Give its importance to a healthy working environment. Sample Scoring Criteria Beginning

Organization

Developing

(1) (2) Unclear flow of Some signs of ideas. and/or abrupt change of ideas.


Approaching Proficiency (3) Some ideas and sequence may be improved.

Proficient (5) Sequence and transition of ideas was effective.

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Details

Inappropriate /off-topic

Too general.

Contained some appropriate details or examples.

Convincingly interpreted.

Sample Rating Scale: Points earned

Equivalent Percentage

10 9 8 7 6 5 4 3 2 1 0

100 97 93 90 86 83 79 76 72 69 65

Lesson 2. Introduction to Electricity After reading this section you will be able to do the following:  

Define electricity and identify the origin of the term. Discuss how electricity can be observed in the world.

What is Electricity? Electricity is a naturally occurring force that exists all around us. Humans have been aware of this force for many centuries. Ancient man believed that electricity was some form of magic because they did not understand it. Greek philosophers noticed that when a piece of amber was rubbed with cloth, it would attract pieces of straw. They recorded the first references to electrical effects, such as static electricity and lightning, over 2,500 years ago.


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It was not until 1600 that a man named Dr. William Gilbert coined the term “electrica,” a Latin word which describes the static charge that develops when certain materials are rubbed against amber. This is probably the source of the word “electricity." Electricity and magnetism are natural forces that are very clos ely related to one another. Watch this 5 minute video about electricity for additional information and knowledge. http://www.youtube.com/watch?v=WbNjrKtR0BY&feature=related

Review 1. Electricity is a naturally occurring force that exists all around us. 2. Electricity comes from “electrica,” a Latin word which describes the static charge that develops when certain materials are rubbed against amber . 3. Electricity gives a wide variety of well-known effects, such as lightning & static electricity.


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Lesson 3. Basic Structure of Matter After reading this section you will be able to do the following:   

Give a basic definition of matter. Describe a molecule. Differentiate an element and a compound.

All matter such as solids, liquids, and gases, is composed of atoms. Therefore, the atom is considered to be the basic building block of matter. Moreover, atoms are almost always grouped together with other atoms to form what is called a molecule. Only a few gases such as helium are composed of individual atoms as the structural unit. Atoms are extremely small and cannot be seen by our naked eyes. Any material that is composed of only one type of atom is called a chemical element, a basic element, or just an element. Any material that is composed of more than one type of atom is called a compound.

Water is a compound made from the elements hydrogen and oxygen.

Activity 1. Fill-in the Missing Word. Directions: Supply the necessary word or group of words that will make the sentence complete. 1. 2. 3. 4.

Matter is composed of _________. A group of atoms is called _________. A material which composed of only one kind of atom is called _______. _____________ is a material composed of more than one kind of atom.


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Activity 2. Water Molecule Directions: On an Oslo Paper draw the water molecule.

Review 1. Matter is composed of atoms. 2. A molecule is a group of atoms grouped together 3. An element is a material composed of only one kind of atom while a compound is a material composed of more than one kind of atom.

Lesson 3. Basic Structure of an Atom After reading this section you will be able to do the following:  

Describe the basic structure of an atom. Explain what holds an atom together.

What is an atom composed of? An atom is the smallest particle of any element that still retains the characteristics of that element. However, atoms consist of even smaller particles. Atoms consist of a nucleus that is surrounded by one or more negatively charged particles called electrons. The nucleus is made up of positively charged particles called protons and neutrons which are neutral. An atom is held together by forces of attraction between the electrons and the protons. The neutrons help to hold the protons together.

Hydrogen Atom

Niels Bohr was a Danish scientist who introduced the model of an atom in 1913. Bohr's model consists of a central nucleus surrounded by tiny particles called electrons that are orbiting the nucleus in a cloud. In our pictures and TLE-IA CONSUMER ELECTRONICS SERVICING

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exercises, the electron appears to orbit in the same path around the nucleus much like the planets orbit the Sun. The electrons, however do not really orbit in the same path. The electrons actually change their orbit with each revolution.

Review 1. Atoms are composed of protons, neutrons, and electrons. 2. The forces of attraction between the electrons and the protons hold an atom together. Activity: The Hydrogen Atom Directions: On an Oslo Paper draw the water molecule.

Lesson 4. Electric Charge After reading this section you will be able to do the following:  

Explain the differences between electrons and protons. Predict what happens when protons and electrons interact with ot her protons or electrons.

Electrons are the smallest and lightest of the particles in an atom. Electrons are in constant motion as they circle around the nucleus of that atom. Electrons are said to have a negative charge, which means that they seem to be surrounded by an electrostatic field.


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Protons are much larger and heavier than electrons. Protons have a positive electrical charge. This positively charged electrostatic field is exactly the same strength as the electrostatic field in an electron, but it is opposite in polarity. Notice that the negative electron (pictured at the top left) and the positive proton (pictured at the right) have the same number of force field lines in each of the diagrams. Like charges repel, unlike charges attract Two electrons will tend to repel each other because both have negative electrical charge. Two protons will also tend to repel each other because they both have positive charge. On the other hand, electrons and protons will be attracted to each other because they have unlike charges. Repel

Repel

Attract

Another important fact about the electrical charges of protons and electrons is that the farther away they are from each other, the less force their electric fields have on each other. Similarly, the closer they are to each other, the more force they will experience from each other due to this invisible force field called an electric field. Activity: Repel or Attract Direction: Based on your observation, write whether the following magnet instances “repel” or “attract” each other. INSTANCES ________1. ________2. ________3.

________4.


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Review 1. Electrons have a negative electrostatic charge and protons have a positive electrostatic charge. 2. A good way to remember what charge protons have is to remember both proton and positive charge start with “P.” 3. Like charges repel, unlike charges attract, similar with magnets.

Lesson 5. The Valence Shell After reading this section you will be able to do the following:  

Define valence shell. Explain what free electrons are and why they are important.

What is the valence shell? Notice that in the copper atom pictured below that the outside shell has only one electron. This represents that the copper atom has one electron that is near the outer portion of the atom. The outer shell of any atom is called the valence shell. When the valence electron in any atom gains sufficient energy from some outside force, it can break away from the parent atom and become what is called a free electron.

Pictured here is an atom of copper, which is much more complex than either an atom of hydrogen or helium. Atoms with few electrons in their valence shell tend to have more free electrons since these valence electrons are more loosely bound to the nucleus. In some materials like copper, the electrons are so loosely held by the atom and so close to the neighboring atoms that it is difficult to determine which electron belong to which atom. Under these conditions, the valence or free electrons tend to drift randomly from one atom to its neighboring atoms. Under normal conditions the movement of the electrons is truly random, meaning they are moving in all directions by the same amount. However, if some outside force acts upon the material, this flow of electrons can be directed through materials and this flow is called electrical TLE-IA CONSUMER ELECTRONICS SERVICING

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current. Materials that have free electrons and allow electrical current to flow easily are called conductors. The top three best conductors of electricity are Silver, Copper and Gold. Many materials do not have any free electrons. Because of this fact, they do not tend to share their electrons very easily and do not make good conductors of electrical currents. These materials are called insulators, examples are rubber, plastic and glass.


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Crossword Puzzle Direction: Complete the crossword by filling in a word that fits each clue. Clues

Review 1. The valence shell is the outer shell of the atom. 2. Some materials have a free electron in their valence shell and this electron can easily move from atom to atom. 3. The free electrons are responsible for electrical current. 4. Conductors are materials that allow the electrical current to flow easily. 5. Insulators are materials that do not allow the electrical current to flow easily.

Lesson 6. Electrical Current After reading this section you will be able to do the following:  

Define amperes. Identify the instrument that is used to measure amperage.

Electricity refers to the energy produced (usually to perform work) when electrons are caused to flow directionally from atom to atom. This movement of electrons between atoms is called electrical current.


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Electricity can be very dangerous. It is important to know how it behave in order to work with it safely. The flow of electrons is measured in units called amperes.

An ammeter is an instrument used to indicate how many amps of current are flowing in an electrical circuit. Open Circuit

Closed Circuit


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Review 1. Amperage is a term used to describe the number of electrons moving past a fixed point in a conductor in one second. 2. Current is measured in units called amperes or amps 3. An Ammeter is used to measure amperage.

Lesson 7. Voltage After reading this section you will be able to do the following:   

Define electromotive force (EMF) and explain how it is measured. Explain why EMF is important to the flow of electrical current. List several examples of sources of electromotive force.

The force that causes the electrons to move in an electrical circuit is called electromotive force (EMF). This force is called electromotive force, or EMF. Sometimes it is convenient to think of EMF as electrical pressure. In other words, it is the force that makes electrons move in a certain direction within a conductor. But how do we create this “electrical pressure” to generate electron flow? There are many sources of EMF. Some of the more common ones are batteries, generators, and photovoltaic cells, just to name a few.

Batteries are constructed so there are too many electrons in one material and not enough in another material. The electrons balance the electrostatic charge by moving from the material with the excess electrons to the material with the shortage of electrons. If these two unbalanced materials within the battery are connected together with a conductor, electrical current will flow as the electron moves from the negatively charged area to the positively charged area. When you use a battery, you are allowing electrons to flow from one end of the battery through a conductor and something like a light bulb to the other end of the battery. The battery will work until there is a balance of electrons at both ends of the battery. Caution: you should never connect a conductor to the two ends of a battery without making the electrons pass through something like a light bulb which slows the flow of currents. If the electrons are allowed to flow too fast the conductor will become very hot which may cause damage to the battery.


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To understand how voltage and amperage are related, it is sometimes useful to make an analogy with water. Look at the picture here of water flowing in a garden hose. Think of electricity flowing in a wire in the same way as the water flowing through the hose. The voltage causing the electrical current to flow in the wire can be considered the water pressure at the faucet, which causes the water to flow. If we were to increase the pressure at the hydrant, more water would flow in the hose. Similarly, if we increase electrical pressure or voltage, more electrons would flow in the wire. Without EMF, there will be no current. Also, we could say that the free electrons of the atoms move in random directions unless they are pushed or pulled in one direction by an outside force, which we call electromotive force, or EMF.

Review 1. Electromotive force causes the electrons to move in a particular direction. 2. EMF is measured measured in units called volts. 3. Some sources of EMF are batteries, generators and photovoltaic cell. cell.

Lesson 8 Resistance After reading this section you will be able to do the following:   

Define resistance. Identify the unit of measurement of resistance. Discuss the similarities between resistance in a wire and the resistance in a water hose.


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Resistance is a term that describes the forces that oppose the flow of electron current in a conductor. This is measured in units called ohms. ohms. All materials naturally contain some resistance to the flow of electron current. If we use our water analogy to help picture resistance, think of a hose that is partially plugged with sand. The sand will slow the flow of water in the hose. We can say that the plugged hose has more resistance to water flow than does an unplugged hose. The same is true with electricity. Materials with low resistance let electricity flow easily. Materials with higher resistance require more voltage (EMF) to make the electricity flow. Is resistance good or bad? Resistance can be both good and bad. If we are trying to transmit electricity from one place to another through a conductor, resistance is undesirable in the conductor. Resistance causes some electrical energy to get lost along the way. However, it is resistance that allows us to use electricity for heat and light. The heat that is generated from electric heaters or the light that we get from light bulbs is due to resistance. In a light bulb, the electricity flowing through the filament, or the t iny wires inside the bulb, causes them to glow white hot.

An important point to mention here is that the resistance resistance is higher in smaller wires. Therefore, if the voltage or EMF is high, too much current will flow through small wires which will make them hot. In some cases, they could be hot enough to cause a fire or even explode. Therefore, it is sometimes useful to add components called resistors into an electrical circuit to restrict the flow of electricity and protect the components in the circuit. TLE-IA CONSUMER ELECTRONICS SERVICING

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Review 1. Resistance is the opposition to electrical current. 2. Resistance is measured measured in units called ohms. ohms. 3. Resistance is sometimes desirable and and sometimes undesirable.

Fill in the blanks. Write the word or group of words that will make the sentence true and complete. 1. A naturally occurring occurring force that exists all around us is called _________. _________. 2. Greek philosophers noticed that when when a piece of amber was rubbed with cloth, it would __________ pieces of straw. 3. Latin word which describes the static static charge that develops develops when certain certain materials are rubbed against amber is called ___________. 4. The natural forces that are very closely related to one one another is electricity and ________. 5. Anything that has mass, weight and occupies space space is called______. called______. 6. A group of of atoms bunched bunched together together is called ________. 7. A material composed of only one kind of atom is called _______. 8. A material composed of more than one one kind of atom is called ________. 9. Composed of of protons, neutrons, neutrons, and electrons and is called ____. 10. The forces of ________ between the electrons and the t he protons hold an atom together. 11. Protons have a ________ electrostatic charge. 12. Like charges repel, unlike charges _________ 13. The outer shell of the atom is called________. 14. The electron that can easily move from f rom atom to atom is called_______. called_______. 15. The free electrons are responsible for _________. 16. A term used to describe the number of electrons moving past a fixed point in a conductor in one second is called________. called________. 17. The actual flow f low of electrons is called _______. 18. This causes the electrons to flow and is called ______. 19. The opposition to electrical current is called _________. 20. Resistance is measured in units called _________.


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B. PROCESS

Lesson 1.

OHM’S Law –

The relationship of Voltage, Current, and Resistance

After reading this section you will be able to: 1. Explain the relationship of voltage, current and resistance. 2. Identify the different unit s of measurement and their corresponding symbols. 3. Compute for voltage, current and resistance. The continuous movement of free electrons through t he conductors of a circuit is called a c u r r e n t , and it is often referred to in terms of "flow," just like the flow of a liquid through a hollow pipe. The force motivating electrons to "flow" in a circuit is called v o l t a g e . Free electrons tend to move through conductors with some degree of friction, or opposition to motion. This opposition to motion is properly called r e s i s t a n c e . The amount of current in a circuit depends on the amount of voltage available to motivate the electrons, and also the amount of resistance in the circuit to oppose electron flow. Just like voltage, resistance is a quantity relative between two points. For this reason, the quantities of voltage and resistance are often stated as being "between" or "across" two points in a circuit. Here are the standard units of measurement for electrical current, voltage, and resistance:

The "symbol" given for each quantity is the standard alphabetical letter used to represent that quantity in an algebraic equation. The "unit abbreviation" for each TLE-IA CONSUMER ELECTRONICS SERVICING

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quantity represents the alphabetical symbol used as a shorthand notation for its particular unit of measurement. And, yes, that strange-looking "horseshoe" symbol is the capital Greek letter Ω. Each unit of measurement is named after a famous expert in electricity: The amp after the Frenchman Andre M. Ampere, the volt after the Italian Alessandro Volta, and the ohm after the German Georg Simon Ohm. The mathematical symbol for each quantity is meaningful. "R" stands for resistance; “V" is for voltage while "I" is thought to have been meant to represent "Intensity" (of electron flow), and the other symbol for voltage, "E," stands for "Electromotive force."

In this algebraic expression, voltage (E) is equal to current (I) multiplied by resistance (R). Using algebra techniques, we can manipulate this equation into two variations, solving for I and for R, respectively:

Let's see how these equations might work to help us analyze simple circuits:

In the above circuit, there is only one source of voltage (the battery, on the left) and only one source of resistance to current (the lamp, on the right). This makes it very easy to apply Ohm's Law. If we know the values of any two of the three quantities (voltage, current, and resistance) in this circuit, we can use Ohm's Law to determine the third.


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In this first example, we will calculate the amount of current (I) in a circuit, given values of voltage (E) and resistance (R):

What is the amount of current (I) in this circuit?

In this second example, we will calculate the amount of resistance (R) in a circuit, given values of voltage (E) and current (I):

What is the amount of resistance (R) offered by the lamp?


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In the last example, we will calculate the amount of voltage supplied by a battery, given values of current (I) and resistance (R):

What is the amount of voltage provided by the battery?

Ohm's Law is a very simple and useful tool for analyzing electric circuits. It is used so often in the study of electricity and electronics that it needs to be committed to memory by students. For those who are not yet comfortable with algebra, there's a trick to remembering how to solve for any one quantity, given the other two. First, arrange the letters E, I, and R in a triangle like this:

If you know E and I, and wish to determine R, just eliminate R f rom the picture and see what's left:

If you know E and R, and wish to determine I, eliminate I and see what's left:


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Lastly, if you know I and R, and wish to determine E, eliminate E and see what's left:

Eventually, you'll have to be familiar with algebra to seriously study electricity and electronics, but this tip can make your first calculations a little easier to remember. If you are comfortable with algebra, all you need to do is commit E=IR to memory and derive the other two formulae from that when you need them! REVIEW: Voltage is measured in volts, symbolized by the letters "E" or "V". Current is measured in amps, symbolized by the letter "I". Resistance measured in ohms, symbolized by the letter "R". Ohm's Law: E = IR ; I = E/R ; R = E/I    

ACTIVITY

Ohm’s Law

Directions: Using the Ohm’s Law, compute for the missing value: 1. I=2A

E=36V


R=?

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2.

I=2A

R=6Ω

E=

I=? 3.

E=25V


R=5Ω

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Lesson 2. Complete Circuit After reading this section you will be able to do the following:  

Explain how a circuit is formed. Identify the sources of electricity.

The electric circuit can be defined as a complete path where electricity flows from a source to the load and back again to the source. Parts of Electric Circuit: 

Source – The Source is where the electricity comes from. It is sometimes called as “source of emf”, refers to a generator, a battery of cell or a transmission power line. It is here where the current or electricity starts to flow. The function of the source is to establish difference from a high (+) to low (-) potential point. The potential difference makes the current to flow.

Batteries


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Power Plant



Path – The Path is all the parts of the circuit where the current or electricity flows. It is the pathway of flowing electricity. The Path is made up of conducting materials or “conductor”. These are materials that conduct electricity and allow electricity to pass through.

Electrical Wires


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Printed Circuit Board (PCB)



Load – Load – Load are devices that consumes electricity on its operation. Examples are light bulbs, television set, electric fan, radios and many others. They are also called current consuming devices. devices.

Light Bulb


Television

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

Switch – Switch – The means of control allows us to control the entire circuit operation. It enables us to regulate electricity. Means of control has the capability to connect or disconnect the flow of electricity from the source to the load. It usually comes in different forms, f orms, maybe a slide switch, push button switch, circuits breakers and others. The means of control functions in two ways; on or off.

Switches

When we connect various components together with wires, we create an electric circuit. The electrons must have a voltage source to create their movement and, of course, they need a path in which to travel. This path must be complete from the EMF source, through the other components and then back to the EMF source. The voltage for any electric circuit can come from many different sources. Some common examples are batteries, power plants, f uel cells.

Power Plant

Flash Light Battery

Car Battery

Fuel Cell


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When we plug an appliance into a wall outlet, voltage and current are available to us. That voltage is actually created in a power plant somewhere else and then delivered to your house by the power wires that are on poles or buried underground.

As a matter of fact, f act, since no current can flow unless there is a voltage source, we also refer to t o these sources as current sources. In addition to the voltage source, we need to have wires and other components to build an electric circuit. Remember that copper wires are conductors since they can easily conduct the flow of electrons.

We may also use resistors or other forms of loads to form a complete circuit. If we do not include resistors in our circuit, there may be too much current flowing to and from our voltage source and we could damage the voltage source.


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Complete Circuit Directions: Draw a complete circuit. Sample illustration.

Review 1. Source, Path, Load and Switch connected together form a circuit. 2. Power plants, photovoltaic cells and batteries are some examples of voltage source

Lesson 3: Types of Circuits After reading this section you will be able to do the following: 1. Identify the different types of circuits. There are three types of electric circuits – series, parallel and combination. Series Circuit We've already come across series circuits. In this type of circuit, the components are arranged end to end and so the electric current flows through the


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first component, then through the next component and so on, until it reaches the battery again. Here's a series circuit to remind you.

If there's a gap in a series circuit or maybe one of the components has broken, the current can't flow and so, the whole circuit turns off. Parallel Circuit In parallel circuits, the components don't have to be end to end because the circuit can have branches.

In a parallel circuit, the current splits as it reaches a branch so the current flows around both branches. If there's a gap or broken component in one of the branches of a parallel circuit, the component(s) in other branches will carry on working.


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Series-Parallel Circuit Also as combination circuit, many real life circuits are combination circuits. See the sample figure used in Parallel Circuits. If we put a switch in each of the branches of a parallel circuit, we can control each component separately.

This is how our homes are wired. Review There are three types of circuit, series circuit, parallel circuit and combination circuit.

Lesson 4: Circuit Diagrams After reading this section you will be able to do the following:  

Explain what circuit diagrams are for. Identify what the symbols in the circuit diagrams stand for.

Circuit diagrams are a visual way of showing circuits. A circuit diagram (also known as an electrical diagram, elementary diagram, or electronic schematic diagram) is a simplified conventional graphical representation of an electrical circuit. A pictorial circuit diagram uses simple images of components, while a schematic diagram shows the components of the circuit as symbols; both types show the connections between the devices. A Block diagram is a diagram of a system, in which the principal parts or functions are represented by blocks connected by lines that show the relationships of the blocks (Details of block diagram will not be covered by this module).


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Electricians and engineers draw circuit diagrams to help them design the actual circuits. Here is an example circuit diagram

. The important thing to note on this diagram is what everything stands for. You see that there are straight lines that connect each of the symbols together. Those lines represent a wire.

This is the Ammeter symbol.

This is the Voltmeter symbol. This is the resistor symbol.

This is the switch symbol.

This is the battery symbol. The important thing to remember about this symbol is that the long bar on top represents the positive terminal on a battery while the short bar on the bottom represents the negative terminal.


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Below is the actual circuit made from the circuit diagram above. Pay close attention to see how similar the diagram and how the real circuit looks.

---------

However, before you do, there are more symbols you will need to learn. Other Electrical Symbols & Electronic Symbols Symbol

Component name

Meaning/Function

Wire Symbols Electrical Wire

Conductor of electrical current


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Connected Wires

Connected crossing

Not Connected Wires

Wires are not connected

Switch Symbols and Relay Symbols SPST Toggle Switch

Disconnects current when open

SPDT Toggle Switch

Selects between two connections

Pushbutton Switch (N.O)

Momentary switch - normally open

Pushbutton Switch (N.C)

Momentary switch - normally closed

Ground Symbols Earth Ground

Used for zero potential reference and electrical shock protection.

Chassis Ground

Connected to the chassis of the circuit

Digital / Common Ground Resistor Symbols Resistor (IEEE)

Resistor reduces the current flow.

Potentiometer (IEEE)

Adjustable resistor - has 3 terminals.

Variable Resistor / Rheostat(IEEE)

Adjustable resistor - has 2 terminals.


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Capacitor Symbols Capacitor

Capacitor

Capacitor is used to store electric charge. It acts as short circuit with AC and open circuit with DC.

Polarized Capacitor

Electrolytic capacitor

Polarized Capacitor

Electrolytic capacitor

Variable Capacitor

Adjustable capacitance

Inductor / Coil Symbols Inductor

Coil / solenoid that generates magnetic field

Iron Core Inductor

Includes iron

Variable Inductor

Power Supply Symbols Voltage Source

Generates constant voltage

AC Voltage Source

AC voltage source

Generator

Electrical voltage is generated by mechanical rotation of the generator

Battery Cell



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Battery


Meter Symbols Voltmeter

Measures voltage. Has very high resistance. Connected in parallel.

Ammeter

Measures electric current. Has near zero resistance. Connected serially.

Ohmmeter

Measures resistance

Wattmeter

Measures electric power

Lamp / Light Bulb Symbols Lamp / light bulb

Lamp / light bulb

Generates light when current flows through

Lamp / light bulb

Diode / LED Symbols Diode

Diode allows current flow in one direction only (left to right).

Zener Diode

Allows current flow in one direction, but also can flow in the reverse direction when above breakdown voltage

Light Emitting Diode (LED)

LED emits light when current flows through


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Photodiode

Photodiode allows current flow when exposed to light

Transistor Symbols NPN Bipolar Transistor

Allows current flow when high potential at base (middle)

PNP Bipolar Transistor

Allows current flow when low potential at base (middle)

Miscellaneous Symbols Motor

Electric motor

Transformer

Changes AC voltage from high to low or low to high.

Electric bell

Rings when activated

Buzzer

Produces buzzing sound

Fuse

The fuse disconnects when current is above the threshold. Used to protect circuit from high currents.

Fuse

Loudspeaker

Converts electrical signal to sound waves

Microphone

Converts sound waves to electrical signal

Antenna Symbols Antenna / aerial

Transmits & receives radio waves


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Antenna / aerial

Dipole Antenna

Two wires simple antenna

Common Electronics Symbol On an Oslo Paper, draw the following electronic components with their corresponding symbols and give the meaning/function of each. NAME

SCHEMATIC SYMBOL

MEANING/FUNCTION

Wire Symbols Electrical Wire Connected Wires Not Connected Wires Switch SPST Toggle Switch SPDT Toggle Switch Pushbutton Switch (N.O) Pushbutton Switch (N.C.) Ground Symbols Earth Ground Chassis Ground Digital Common Resistors Fixed Resistor Variable Resistor Capacitors Capacitor (Fixed) Polarized Capacitor Variable Capacitor Inductor/Coils Inductor Iron Core Inductor Variable Inductor TLE-IA CONSUMER ELECTRONICS SERVICING

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Power Supply Voltage Source AC Voltage Source Battery Cell Battery Meter Voltmeter Ammeter Ohmmeter Lamp/Lights Lamp/Light Bulb Diodes Diode Zener Diode Light Emitting Diode Photodiode Transistors NPN PNP Miscellaneous Fuse Buzzer Loudspeaker Microphone Lesson 5: Resistor After reading this section you will be able to do the following: 1. Define resistor. 2. Identify types of resistor. Resistors ( R ), are the most fundamental and commonly used of all the electronic components. There are many different types of resistors available, from very small surface mount chip resistors up to large wirewound power resistors. The principal job of a resistor within an electrical or electronic circuit is to "resist" or to impede the flow of electrons.


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A Typical Fixed Type Resistor Resistors are "Passive Devices", that is, they contain no source of power or amplification but only attenuate or reduce the voltage signal passing through them. This attenuation results in electrical energy being lost in the form of heat as the resistor resists the flow of electrons through it. Most resistors produce a voltage drop across themselves when electrical current flows through them because of Ohm's Law and different values of resistance produce different values of current or voltage. Resistance is the opposition to the flow of current. This can be very useful in electronic circuits by controlling or reducing either the current flow or voltage produced across them. In all Electrical and Electronic circuit diagrams and schematics, the most commonly used symbol for a fixed value resistor is that of a "zig-zag" type line with the value of its resistance given in Ohms, Ω. Resistors have fixed resistance values from less than one ohm, ( <1Ω ) to well over tens of millions of ohms, ( >10MΩ ) in value. Fixed resistors have only one single value of resistance, for example 100Ω'sbut variable resistors (potentiometers) can provide an infinite number of resistance values between zero and their maximum value. Standard Fixed Type Resistor Symbols

The symbol used in schematic and electrical drawings for a Resistor can either be a "zig-zag" type line or a rectangular box.

All modern fixed value resistors can be classified into four broad groups; Carbon Composition Resistor - Made of carbon dust or graphite paste, low wattage values Film or Cermet Resistor - Made from conductive metal oxide paste, very low wattage values Wire-wound Resistor - Metallic bodies for heatsink mounting, very high wattage ratings

Composition Type Resistors Carbon Resistors are the most common type of Composition Resistors. Carbon resistors are a cheap general purpose resistor used in electrical and electronic circuits. Their resistive element is manufactured from a mixture of finely ground carbon dust or graphite (similar to pencil lead) and a non-conducting ceramic (clay) powder to bind it all together. TLE-IA CONSUMER ELECTRONICS SERVICING

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Carbon Resistor

The Carbon Composite Resistor is a low to medium type power resistor. Power rating is from 0.25 or 1/4 of a Watt up to 5 Watts. Carbon composite resistors are very cheap to make and are therefore commonly used in electrical circuits. However, due to their manufacturing process carbon type resistors have very large tolerances so for more precision and high value resistances, film type resistors are used instead.

Film Type Resistors The generic term "Film Resistor " consist of Metal Film, Carbon Film and Metal Oxide Film resistor types, which are generally made by depositing pure metals, such as nickel, or an oxide film, such as tin-oxide, onto an insulating ceramic rod or substrate.

Film Resistor Film type resistors also achieve a much higher maximum ohmic value compared to other types and values in excess of 10MΩ (10 Million Ω´s) are available. TLE-IA CONSUMER ELECTRONICS SERVICING

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Metal Film Resistors have much better temperature stability than their carbon equivalents, lower noise and are generally better for high frequency or radio frequency applications. Metal Oxide Resistors have better high surge current capability with a much higher temperature rating than the equivalent metal film resistors. Metal Film Resistors are prefixed with a "MFR" notation (eg MFR100kΩ) and a CF for Carbon Film types. Metal film resistors power rating is 0.05 (1/20th) of a Watt up to 1/2 Watt. Generally speaking Film resistors are precision low power components. Wirewound Type Resistors Another type of resistor, called a Wirewound Resistor , is made by winding a thin metal alloy wire (Nichrome) or similar wire onto an insulating ceramic former in the form of a spiral helix similar to the film resistor above. These types of resistors are generally only available in very low ohmic high precision values (from 0.01 to 100kΩ) due to the gauge of the wire and number of turns possible on the former making them ideal for use in measuring circuits and Whetstone bridge type applications. They are also able to handle much higher electrical currents than other resistors of the same ohmic value with power ratings in excess of 300 Watts. These high power resistors are moulded or pressed into an aluminum heat sink body with fins attached to increase their overall surface area to promote heat loss and cooling. These types of resistors are called "Chassis Mounted Resistors". They are designed to be physically mounted onto heatsinks or metal plates to further dissipate the generated heat increasing their current carrying capabilities even further .


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Wirewound Resistor

Wirewound resistor types are prefixed with a "WH" or "W" notation (eg WH10Ω) and are available in the WH aluminium cladded package with power ratings from 1W to 300W or more.

Variable Resistor

Variable resistors or potentiometers are used in many areas of electronics. They are used for volume and gain controls as well as a variety of other applications. Preset variable resistors or potentiometers are also used in circuits that need a small adjustment to be made to set the circuit up after manufacture. TLE-IA CONSUMER ELECTRONICS SERVICING

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For convenience variable resistors are made by having a fixed resistor with a variable tapping point. As a result of this arrangement these devices are often called potentiometers or "pots" for short. Here the potentiometer consisted of a length of resistance wire with a tapping point that could be moved along the wire - the same configuration as that used in these variable resistors. As shown in the diagram below, a variable resistor consists of a track which provides the resistance path. Two terminals of the device are connected to both the ends of the track. The third terminal is connected to a wiper that decides the motion of the track. The motion of the wiper through the track helps in increasing and decreasing the resistance.

The track is usually made of a mixture of ceramic and metal or can be made of carbon as well. As a resistive material is needed, carbon film type variable resistors are mostly used. They find applications in radio receiver circuits, audio amplifier circuits and TV receivers. A track made in a straight path is called a slider. As the position of a slider cannot be seen or confirmed according to the adjustment of resistance, a stopping mechanism is usually included to prevent the hazards caused due to over rotation. There are two major types: 1. R o t a r y : The most common form of variable resistor or potentiometer is a rotary version. This version of potentiometer uses a rotary motion to move the slider around a track that compromises most of a circle, with contacts at either end of the track in the area where part of the circle is missing. This form is widely used with knobs on a spindle for the actual control, and they are found in many applications from providing adjustments on test equipment through to being used for volume controls on domestic radios.


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2. Slider: Slider controls are those variable resistors that slide in a linear fashion, i.e. in a straight line. These controls take up more front panel space, but are much easier to use under some circumstances. For example they are widely used for audio mixers and lighting desks. The advantage of sliders is that it is easier to control them quite precisely and compare the relative positions of a number of sliders. It is also possible to control a number of sliders together.

Review 1. A Resistor is an electronic component used to resist the flow of electrons. 2. There are many types of resistors, for fixed type; Carbon Composition, Film or Cermet, and Wirewound. The variable types are rotary and slider.


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Lesson 6: Other Electronic Components After reading this section you will be able to do the following: 1. Identify other electronic components and explain their basic f unction. Capacitor A device that consists essentially of two conducting surfaces separated by a dielectric material like air, paper, mica, ceramic, glass, or Mylar. It makes it possible to store electric energy. Electrons are detained within a capacitor. This, in effect, is stored electricity . The component is designed intentionally to have a definite amount of capacitance. This capacitance is a property that exists whenever insulating material permits the storage of electricity. It is measured in Farad (F) micro Farad (μF), nano Farad (nF), and picoFarad (pF). Characteristics of Capacitor: 1. It can store electric charge even though the voltage source is already disconnected. 2.It can discharge electrical voltages.

Fixed type capacitor

Electrolytic

Tantalum


Mica

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Symbols of Capacitor

Diode A diode is a two-terminal electronic component with asymmetric transfer characteristic, with low (ideally zero) resistance to current flow in one direction, and high (ideally infinite) resistance in the other. It is a semiconductor device.

The most common function of a diode is to allow an electric current to pass in one direction (called the diode's forward direction), while blocking current in the opposite direction (the reverse direction). Thus, the diode can be viewed as an electronic version of a check valve. This unidirectional behavior is called rectification, and is used to convert alternating current to direct current, these diodes are forms of rectifiers. Transistor A semiconductor device used to amplify and switch electronic signals and electrical power. It is composed of semiconductor material with at least three terminals for connection to an external circuit.


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Integrated Circuit (IC) An integrated circuit, or IC, is small chip that can function as an amplifier, oscillator, timer, microprocessor, or even computer memory. An IC is a small wafer, usually made of silicon, that can hold anywhere from hundreds to millions of transistors, resistors, and capacitors. These extremely small electronics can perform calculations and store data.

Review Capacitor is an electronic component used to charge and discharge electric energy. Diode is an electronic component used to allow the current to pass in one direction only. Transistor is used mainly for switching amplification purposes. Integrated Circuits or ICs can function as an amplifier, oscillator, timer, microprocessor or memory; and can hold hundreds to millions of transistors, resistors and capacitors.


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LESSON 7. BASIC HAND TOOLS & EQUIPMENT After reading this section you will be able to: 1. Identify some basic tools and equipment and explain their uses. 2. Value the proper maintenance of hand tools and equipment.

Sic t

Assembling an electronic project and making it work is a good start in helping one to learn troubleshooting methods as well as becoming familiar with your tools, test equipments, electronic schematics and component color codes. It's hard to produce a good project/product or service unless proper electronic tools and knowledge of using them and observing safety precautions are adequate. Some of the basic tools & equipment that should prove useful are listed below. Electric Drill and Drill Bits Electric drill and drill bits in the range of 1/8 inch to 1/2 inch will come in handy when you need to drill holes on the printed circuit board (PCB) that has been etched. Drilling of plastic or metal enclosure that houses the printed circuit board are sometimes necessary.


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Electric Drill

A suitable PCB Mini Hand Drill can be easily obtained from any electronic shop.

Soldering Iron In large and heavy metal work, welding is used in joining metals permanently. In electronics work, soldering is used to join pigtails of components, transistor leads, and IC pins among others. Soldering is the process of heating materials, and joints to be soldered and applying solder on the heated joints to ensure permanent connection. TLE-IA CONSUMER ELECTRONICS SERVICING

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Soldering Iron A 30 Watt to 40 Watt soldering iron with tips of 1/8 inch to 1/2 inch can be used for soldering of through hole components. Soldering of surface mount components may require smaller tips depending on the sizes of the components. Soldering iron normally will last a long time if it is taken care of properly by keeping the tips clean and well tinned. Basic Soldering Guide


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What Is Soldering? Soldering is a process in which two or more metal items are joined together by melting and flowing a filler metal (solder ) into the joint, the filler metal having a lower melting point than the workpiece. Soldering differs from welding in that soldering does not involve melting the work pieces. In soldering, the filler metal melts at a higher temperature, but the workpiece metal does not melt. Formerly nearly all solders contained lead, but environmental concerns have increasingly dictated use of lead-free alloys for electronics and plumbing purposes.


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Solder is a thin tube, usually rolled in spools, made of various metal alloys. Its job is to hold the individual components together. The individual components and their quantities can vary, but for computer electronics, you’re usually looking at a 60% tin and 40% lead. Lead-free solder is also available, though it has higher melting temperatures and less “wettability,” meaning you may need a better soldering iron to use it and removing it can be more tedious.

It is better to use lead free solder because it functions well and is environmentally friendly.

A solder ’s tube is filled with “flux,” a substance that gets rid of oxidation and helps clean the surfaces involved in the fusing process. For electronic use, we want rosin-core/rosin-flux solder. Acid-flux is used in plumbing and the acid can damage the sensitive components on PCBs.


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Wire Stripper

Wire stripper is used to strip off wire insulator from its conductor before it is used to connect to another wire or soldered into the printed circuit board. Some wire stripper or wire cutter has a measurement engraved on it to indicate the length that can be stripped. Long nose Pliers

A pair of 4-inch long nose pliers will come in handy when you need to hold components that have short leads that need to be soldered onto the PCB but will be too hot to handle with bare hands. It will also be useful to hold the component that needs to be de-soldered from the board.


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Side-Cutting Pliers

A pair of 4-inch side cutting pliers will come in handy when one needs to trim off excess component leads on the printed circuit board. It can also be used to cut wires into shorter length before being used. Tweezers

Small tweezers are used to hold much smaller components especially when doing soldering and de-soldering of surface mount components.


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Allen Wrench set

Allen wrench set is sometimes used to unscrew or screw Allen type of screws. Philips Screwdrivers

Various sizes of Philips head screwdrivers will be handy as a lot of electronics projects that use screws are Philips Head type.


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Flat Head Screwdrivers

Flat head screwdrivers of various sizes are also necessary as many screws commonly used are of this type. Hammer

A small, light hammer will be useful when assembling projects that involve casing.


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Socket wrench sets

A socket wrench set includes nut drivers, hex drivers, and starters in assorted sizes that will come in handy during the assembly work of electronics project.


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Blade Cutter

A Blade Cutter will be useful when one need to cut PCB, wires or remove some copper from the printed circuit board. Equipment Aside from hand tools, certain equipment are also needed for more accurate and quality output. Three of the commonly used equipment are presented here for you to be familiar with their uses and the proper way of maintaining them. a. Oscilloscope. An oscilloscope (commonly abbreviated CRO, for cathode ray oscilloscope, or simply scope) is a piece of electronic test equipment that allows signal voltage to be viewed.


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b. Signal generator . A device which produces simple waveforms.

Such devices contain an electronic oscillator, a circuit that is capable of creating a repetitive waveform. These are typically used in simple electronics repair and design where they are u sed to stimulate a circuit under test .

Oscilloscope and signal generator should be given regular check-up for at least once a week by connecting them in the power line. This will prevent their components from having moisture that might cause trouble in their circuits.

c. Volt-OHM-Milliammeter (VOM). A handheld device that combines three functions: as a voltmeter that measures both ac and dc voltages: an ohmmeter that measures resistance: and milliammeter that measures small amount of dc current. It is called Multitester (Multitester) or Multimeter (Multi-tester). It can measure to a very high degree of accuracy. They can be used to troubleshoot electrical problems in a wide array of industrial and household devices such as electronic equipment, motor controls, domestic appliances, power supplies, and wiring systems. As safety precautions in the maintenance of this instrument, the following should be observed:


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General Rule for Analog: 









Always rest the function switch at 250Vac if an off position is not available in the instrument. For current and voltage measurement, always set the function switch in the correct setting which is a little higher than the expected current or voltage present in the circuit.

Optimise the range for the best reading. If possible adjust it so that the maximum deflection of the meter can be gained. In this way the most accurate reading will be gained. When making measurements, Keep your fingers behind the f inger guards on the test probes. Place the instrument in a cool dry place, away from any magnetic devices, and free from vibrations.


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Hand Tools Classification There are four different types of hand tools according to their uses:











Cutting Tools:These are used to cut a physical object into pieces. For example: side cutting pliers and blade cutters. Gripping Tools: These tools are used for gripping objects by using leverage. For example: long nose pliers and twizzers. Striking Tools: The striking tools are the most widely used tools. Chiseling, punching and riveting can be done properly using striking tools. Hand-held striking tools have been used in a variety of disciplines as leverage devices providing a striking force to complete endless variety of tasks. For example: hammers & chisels Driving Tools: These are designed in such a way that insertion, tightening, loosening, removing screws, bolts, nails or other pointed objects or hard -to-turn items are done by applying torque. For example: screwdrivers, nut drivers and wrenches. Struck or Hammered Tools: These tools are used for forcing a bolt, pin, or rivet in or out of a hole. For example: punches, nail sets, chisels .

Maintenance Tips of Electronic Tools Good quality tools can last a lifetime if they are taken care of properly. Ensure that the tools are used only for their intended purposes, keep them lubricated with a light film of oil to inhibit rust, keep the tools clean and sharp, keep the soldering tips clean and well tinned and ensure that proper use of the tools are always adhered to by following the instructions in the proper use of tools.

Common Faults in Using Hand Tools

Pliers: 

Do not increase the handle length of the pliers to more leverage. Use a larger pair of pliers or bolt cutters if necessary.

Do not substitute pliers for a wrench when turning bolts and nuts. Pliers cannot grip these items properly and might cause a slip and cause an accident. 


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





Never use pliers as a hammer on the handle. Such abuse is likely to result in cracks or breaks. Cut hardened wire only with pliers designed for that purpose. Always cut the wire in right angle. Never rock from side to side or bend wire back and forth against the cutting edges.

Screwdrivers:







Never use screw drivers as a pry bar, chisel, and punch stirrer or scraper. Never use screwdrivers with broken or worn-out handles. Screwdrivers of these kinds should have tags to indicate t hat it is defective. Never use pliers on a screwdriver for extra leverage. Only use wrench or screwdrivers specially designed for the purpose.

Utility Knives/ Blades: 





Do not use dull blades because they require more force, thus, they are more likely to slip. Replace the blades when they start to “tear” instead of cut. Never leave a knife unattended with the blade exposed. Don’t bend or apply side loads to blades by using them to open cans or loosen tight cover of containers. Blades are brittle and can snap easily.


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Inventory of Tools 1. Take hold of the tools found in your shop/house and acquaint yourself with their parts. Try to identify the name and the use of each while being extra careful not to damage the tools nor hurt yourself. 2. Categorize some available tools in your shop according to: Cutting Tools

Gripping Tools

Striking Tools

Driving Tools

Additional Activities: 

The teacher may bring his/her class to an electronic shop and let the students observe how the skilled electronic technician uses different kinds of tools.



View a video about how skilled electronic technician uses different kind of tools. (The teacher may show this video entitled Collin’s Lab:Electronic Tools at http://www.youtube.com/watch?v=Kv7Y8nAOoFE ).

Review: 1. Some basic hand tools with the corresponding uses are: Electric drill is used to drill holes on PCB; Soldering iron is used to join metals and solder electronic components on PCB; Wire stripper is used to strip off wire insulators; Long nose pliers are used to hold small components; Side cutting pliers are used to cut wires and trim off excess component leads; and Screwdrivers are used to drive or remove screw. Some measuring equipments with their uses are: Oscilloscope allows signal voltage to be viewed; Signal generator produces simple waveforms; and Multitester (VOM) can measure voltage, resistance and small amount of current. Tools can be categorized to Cutting, Gripping, Striking and Driving. 2. Well maintained tools and equipment are important so that they are readily available and function properly


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IDENTIFICATION. Identify the following tools/equipment based on the cited uses. 1. Used to join metals and solder components. 2. Used to strip insulators. 3. Used to hold small components. 4. Used to drill holes on PCB. 5. Used to cut wires. 6. Used to drive screw. 7. Used to cut unnecessary copper on PCB. 8. Used to measure voltage, resistance and current. 9. Produces simple waveforms. 10. Used to view signal.

ESSAY. Write the importance of well maintained tools and equipment. Sample Scoring Criteria

Organization

Details

Beginning

Developing

(1) No idea or unclear flow of ideas.

(2) Some signs of and/or abrupt change of ideas.

Inappropriate /off-topic

Too general.

Approaching Proficiency (3) Some ideas and sequence may be improved. Contained some appropriate details or examples.

Proficient (5) Sequence and transition of ideas was effective. Convincingly interpreted.

Sample Rating Scale: Points earned

Equivalent Percentage

10 9

100 97


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8 7 6 5 4 3 2 1 0

93 90 86 83 79 76 72 69 65

C. REFLECT AND UNDERSTAND

Lesson1/Activity1: Resistor Color Coding We learned in the previous lesson that there are many different types of Resistors available and that they can be used in electronic circuits to control the flow of current or voltage in many different ways. But in order to do this, the actual resistor needs to have some form of "resistive" or "resistance" value. Resistors are available in a range of different resistance values from fractions of an Ohm ( Ω ) to millions of Ohms. Obviously, it would be impractical to have available resistors of every possible value for example, 1Ω,2Ω, 3Ω, 4Ω etc, because literally hundreds of thousands, if not millions of different resistors would need to exist to cover all t he possible values. Instead, resistors are manufactured in what are called "preferred values" with their resistance value printed onto their body in colored ink.

4 Colored Bands


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The resistance value, tolerance, and wattage rating are generally printed onto the body of the resistor as numbers or letters when the resistors body is big enough to read the print, such as large power resistors. But when the resistor is small such as a 1/4W carbon or film type, these specifications must be shown in some other manner as the print would be too small to read. So to overcome this, small resistors use colored painted bands to indicate both their value with the physical size of the resistor indicating its wattage rating. These colored painted bands produce a system of identification generally known as Resistors Color Code. A resistors color code markings are always read one band at a time starting from the left to the right, with the larger width tolerance band oriented to the right side indicating its tolerance. By matching the color of the first band with its associated number in the digit column of the color chart below the first digit is identified and this represents the first digit of the resistance value. Again, by matching the color of the second band with its associated number in the digit column of the color chart we get the second digit of the resistance value and so on as illustrated below:


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The Standard Resistor Color Code Chart.


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The Resistor Color Code Table (Four Bands).

Color

Digit

Digit

Multiplier

Tolerance

(Leftmost (Stands (Represents band for for the multiplier first second or number of significant significant zeros after the digit) digit) two digits) Black

0

0

1 10

Brown

1

1

± 1% (0) 100

Red

2

2

± 2% (00) 1,000

Orange

3

3 (000)

Yellow

4

4

10,000 (0000) 100,000

Green

5

5

± 0.5% (00000) 1,000,000

Blue

6

6

± 0.25% (000000)


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10,000,000 Violet

7

7

± 0.1% (0000000)

Grey

8

8

White

9

9 0.1 (Decimal point is after the first significant digit)

Gold

± 5%

0.01 (Decimal point is before the first significant digit)

Silver

None

± 10%

± 20%

Calculating Resistor Values It is important to understand the Resistor Color Code system and understand how to apply it in order to get the correct value of the resistor. The "lefthand" or the most significant colored band is the band which is nearest to a connecting lead with the color coded bands being read from left-to-right as follows; Digit, Digit, Multiplier = Color, Color x 10 color in Ohm's (Ω's) For example, a resistor has the following colored markings; Yellow Violet Red = 4 7 2 = 4 7 x 102 = 4700Ω or 4k7. The fourth and fifth bands are used to determine the percentage tolerance of the resistor. Resistor tolerance is a measure of the resistors variation from the specified resistive value and is a consequence of the manufacturing process and is expressed as a percentage of its "nominal" or pr eferred value. Most of the four band resistors have tolerances of 5%, 10% and 20%. The color code used to denote the tolerance rating of a resistor is given as; Brown = 1%, Red = 2%, Gold = 5%, Silver = 10 %


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If resistor has no fourth tolerance band then the default tolerance would be at 20%. Examples: 1. The value of a resistor is 10 Ohms with a tolerance of 5%. Let us find out from the 4 Bands Resistor Color Chart what would be the color bands of the resistor.

black brown

black gold

1 0 5% Reading: 10 ohms

The colors that you have located in the table should match the digit and multiplier in the first example. Continue checking with other examples. 2.

The value of the resistor is 100 ohms with a tolerance of 10%. black brown

brown silver

1 0 0 10 % Reading: 100 ohms

3.

In this example, the value of the resistor is 2000 0hms. Three

zeroes Represent a thousand which can be substitute for abbreviation with Letter K. Thus the value of the resistor will appear as 2 K ohms. black

red

red

2

0


00 Page 76

Reading: 2,000 ohms or 2K

4. In example 4, the third color band is gold, multiply the first two digits by 0.1. Therefore, the resistance would be 4.7 ohms. violet

gold

yellow

4 7 0.1 Reading: 4.7 ohms

5. In example 5, the third color is silver so the decimal multiplier is .01.The decimal point is placed before the first digit. The reading will be .22 ohms. red red

silver

2 2 .01 Reading: .22 ohms

It is sometimes easier to remember the resistor color code by using mnemonics or phrases that have a separate word in the phrase to represent each of the Ten + Two colors in the code. However, these sayings are often very crude but never the less effective for remembering the resistor colors. Here are just a few of the more "cleaner" versions but many more exist: Black

Brown

Red

Orange Yellow

Bad

Boys

Ring

Our

Young

Green Girls

Blue Violet Gray But

Vicky Goes Without

Bad Boys Ring Our Young Girls But Vicky Gives Willingly-- Get Some Now (This one is only slightly better because it includes the tolerance bands of Gold, Silver, and None).


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Additional Information: Some resistors, particularly metal film types, are marked with a number or letter code to indicate the value and tolerance instead of the color code.

3K3J Value: 3,300 ohms + 5% or 3.3K, + 5%

The letter K represents both the multiplier and the location of the decimal point in the number of the resistor. Multipliers R K M

Value Represented 1 1000 1000000

The tolerance is given by the last letter. Tolerance F G J K M

Value Represented 1% 2% 5% 10 % 20 %

Assessment 1: Resistor Color Coding Multiple Choice: Choose the letter of the best answer (Ask the students to show their computation). 1. What is the value of a resistor with a Blue-Black-Orange-Gold Color Code? A. 600 Ohms ± 5% B. 6K Ohms±5%

C.60K Ohms±5%

D. 600K Ohms ±5%

2. What is the value of a resistor with a Red-Violet-Brown-Silver Color Code? A. 27 Ohms±10%

B. 270 Ohms±10% C. 2.7K Ohms±10% D. 27K Ohms±10%


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3. What is the value of a resistor with a Yellow-Yellow-Yellow-Gold Color Code? A. 440 Ohms±5% B. 4.4K Ohms±5%

C. 44K Ohms±5%

D. 440K Ohms±5%

4. What is the value of a resistor with a Green-Blue-Black-Silver Color Code? A. 56 Ohms±10%

B. 560 Ohms±10% C. 5.6K Ohms±10% D. 56K Ohms±10%

5. What is the color of representing 20% tolerance? A. Black

B. Silver

C. Gold

D. No Color

Additional Activity/Assessment: Resistor Tabulation Materials: 10 pieces - Carbon resistors, 1 watt, assorted values 1 pc - Resistor Tabulation form Procedures: 1. Arrange the resistors on a piece of styrofor. 2. Identify the colors of the resistors one by one and record them in t he resistor tabulation form. 3. Compute for the resistance value of each resistor by following the color coding scheme. 4. Write the value of the resistance in the t abulation form.


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Sample Resistor Tabulation Form (Photocopy this or simply copy on your notebook) #

1st COLOR BAND

2nd COLOR BAND

3RD COLOR BAND

TOLERANCE COMPUTED VALUE

1 2 3 4 5 6 7 8 9 10 Performance Test Learner’s Name:

Date:

Competency:

Test Attempt 1

st

2

nd

rd

3

Directions:

OVERALL EVALUATION CALL THE TEACHER and ask him / her to assess your performance in the following critical task using the performance

LEVEL PERFORMANCE LEVEL ACHIEVED


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criteria below.

4 - Can perform this skill without supervision supervision and with initiative and adaptability adaptability to t o problem situations. 3 - Can perform this skill satisfactorily without assistance or supervision.

You will be rated based on the overall evaluation on the right side.

2 - Can perform this skill satisfactorily but requires some assistance and/or supervision. 1 - Can perform parts of this skill satisfactorily, but requires considerable considerable assistance and/or supervision.

The teacher will affix his/her initial on the level achieved. PERFORMANCE STANDARDS For acceptable achievement, all items should receive a "Yes" response. 1. Can recite the colors of the color coding chart in order without looking at the chart.

Yes

No

N/A

2. Can identify the first color of the carbon resistor. 3. Can interpret equivalent numerical value of each color in the chart 4. Can calculate the color coded value of the resistor. 5. Can give the over-all value of the resistor after calculation. Lesson 2/Activity 2: Proper Use of Soldering Iron

Many who’ve never used a soldering iron are afraid of damaging the equipment, but more important is the danger to yourself! yourself! Soldering irons get get really hot. Be sure to wear safety glasses, keep loose clothing and hair out of the way, and be careful with your fingers. Better still, use protective gloves. Solder can contain lead, so be sure t o wash your hands thoroughly after handling it. It is also really important to work in a well-ventilated area because the fumes from the rosin can cause damage to your lungs when inhaled.


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A. Cleaning and Tinning the Tip

In order to conduct heat properly, your soldering iron needs to be free of any old solder. After being exposed to air, it oxidizes and thus insulates against heat. We want heat to conduct so that we can apply everything quickly and efficiently. A dirty tip means that you’ll have to hold the iron on l onger and risk heat damage to the component or PCB. Keep a wet sponge handy, and after the soldering iron is fully heated, softly scrape it against the sponge to remove old solder. The tip should be clean and shiny, or at least very close to it. Tinning protects the tip and allows heat to conduct better via the presence of new solder. On the hot iron, carefully apply a small amount of fresh solder and coat the tip. It should still be shiny if you’ve done it right. As soon as you tin the tip , start soldering your components together. After a few joints, clean and re-tin again before putting your iron away into storage. This will really help increase the longevity of your tool.


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Joining Parts on PCB

Hold the iron in your dominant hand and a long piece of solder in your other hand. When soldering two components together, you want to touch the area where they join with the soldering iron. Hold it there for about a second, then slide the solder underneath the tip of the iron, sandwiching it to the PCB (refer to above image, cursor points to solder). Hold it for another second or two, feeding in how much solder you need. This amount will vary depending on the project, application, and diameter of the solder, so check your instructions and study the pictures to get a good idea of the end result.


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Now, this is really important. Pull away the solder first, and continue holding the iron for another second. This allows the solder to continue to melt and pool, forming a good joint. Then, you can remove the iron. The total process shouldn’t take more than 5 seconds, and usually you are aiming for 3-4. Wait a few seconds and don’t disturb the solder. It cools very quickly, but moving or blowing on the joint will cause it to deteriorate. A bad solder connection will look really oxidized, overly dull, and grainy. It also sort of looks like a ball of solder formed on the area. A good connection should be smooth and uniform and its sides will be concave. It won’t look like a raised ball, it’ll look flat. Soldering Wires •

Remove the insulator of the wire you want to connect together.


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

• •



Cross the twisted ends of the wires to be soldered.

Starting at the cross section, twist the wires together around themselves. Twist the stands of wire to be soldered so that it becomes one and it will be easy to solder.

Solder the wires together

Remember • • • • • • • • • •

Clean the tip of the soldering iron gun regularly. Tin the tip of soldering iron. Maintain the pointed tip of soldering iron and reshape it, if necessary. Apply right amount of solder on the preheated metallic surface and not directly to the tip of the soldering iron. Let the melted solder flow freely around the joint surface. Solder the joint as quick as possible to avoid extreme heat on the components. Reheat the cold soldered joint. Use a soldering stand to avoid the tip to get in contact with combustible materials or your skin. Hold the excess terminal lead while cutting to prevent being hit by flying Cut excess terminal wires.


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Additional Activity Directions: Using an actual soldering iron and soldering gun compare the features and characteristics of the two soldering tools.

Based on the results of the previous activity, which do you prefer to use? Why? ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ _____________________


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Lesson 3/Activity3. Desoldering When removing a connection or undoing a mistake, you can often resolder over the original and add a touch of new solder. If you want to t ake the extra step and do it right, you can remove the old solder completely and start with a fresh work area. There are two tools you can use for this, a vacuum-based “solder sucker,” or a solder wick.

A solder sucker is essentially a tiny hand-held syringe-like pump. It creates and uses vacuum pressure to suck solder off of whatever it’s on. It’s a great tool to have and works well.

Removing component components in PCB using a desoldering pump 1. Set the pump by pushing the spring- loaded plunger down until it locks. 2. Apply both the pump nozzle and the tip of your soldering iron to the joint. 3. Wait a second or two for the solder to melt. 4. Then press the button on the pump to release the plunger and suck the molten solder into the tool. 5. Repeat if necessary to remove as much solder as possible. 6. The pump will need emptying occasionally by unscrewing the nozzle. After removing most of the solder from the joint(s), you may be able to remove the wire or component lead straight away allowing a few seconds for it to cool. If the joint does not come apart easily, apply your soldering iron to melt the remaining traces of solder at the same time as while pulling the joint apart, taking care to avoid burning yourself. 87

Lesson 4ctivity 4/A. How To Use and Read a Multimeter Using a multimeter is quite bit difficult for the first time especially the analog type one unlike the digital which is more convenient to use for beginners. Every multimeter has its own user manual when you purchase it. A Multimeter is used to measure voltages AC or DC, currents and resistance, continuity and electronics components.

PARTS OF A MULTIMETER Sanwa YX-360TR/Sanwa-YX361TR

1.) Zero Position Adjuster 2.) Indicatot Pointer 3.) Indicator Scale

7.) Measuring Terminal + 8.) Measurin Terminal - COM 9.) Series Terminal Capacitor OUTPUT 88

4.) Continuity Indicating LED ( CONTINUITY ) 5.) Range Selector Switch knob 6.) 0-ohms adjusting knob /0- centering meter (NULL meter) adjusting knob

10.) Panel 11.) Rear Case

EXPLANATION ABOUT THE SCALE

1.) Resistance (OHMS) scale 2.) DCV, A scale and ACV scale (10V or more) 3.) 0-centerig (NULL) +/- DCV scale 4.) ACV 2.5 (AC 2.5V) exclusive scale 5.) Transistor DC amplification factor (hFE) scale 6.) 1.5 baterry test (BATT 1.5V) 7.) OHMS range terminal to terminal current (Li) scale) 8.) OHMS range terminal to terminal voltage (LV) scale 9.) Decibel (dB) scale 10.) Continuity Indicating LED 11.0 Mirror: To obtain most accurate readings, the mirror is deviced to make operator eyes, the indicator pointer, and the indicator pointer reflexed to the mirror put together in line. 89

How to Measure Resistance Multimeter with selector set to "Ohms". This meter only has a single Ohms range. Set the multimeter to Ohms or Resistance (turn meter on if it has a separate power switch). Understand that resistance and continuity are opposites. When there is little resistance there is a great deal of continuity. Conversely, when there is a great deal of resistance, there is little continuity. With t his in mind, when we measure resistance we can make assumptions about continuity based on the resistance values measured. Observe the meter indication. If the test leads are not in contact with anything, the needle or pointer of an analog meter will be r esting at the left most position. This represents an infinite amount of resistance, or an "open circuit"; it is also safe to say there is the no continuity, or path between the black and red probes. Careful inspection of the dial should reveal the OHM scale. It is usually the top-most scale and has values that are highest on the left of the dial (a sideways "8" for infinity) and gradually reduce to 0 on the right. This is opposite of the other scales; they have the lowest values on the left and increase going right. Connect the black test lead to the jack marked "Common" or "-" Connect the red test lead to the jack marked with the Omega (Ohm symbol) or letter "R" near it. Set the range (if provided) to R x 100. Hold the probes at the end of the test leads together. The meter pointer should move fully to the right. Locate the "Zero Adjust" knob and rotate so that the meter indicates "0" (or as close to "0" as possible). Note that this position is the "short circuit" or "zero ohms" indication for this R x 1 range of this meter. Always remember to "zero" the meter immediately after changing resistance ranges. Replace batteries if needed. If unable to obtain a zero ohm indication, this may mean the batteries are weak and should be replaced. Retry the zeroing step above again with fresh batteries. When measuring the resistance of something like a light bulb, locate the two electrical contact points of the bulb. These will be the threaded base and the center of the bottom of the base. Have a helper hold the bulb by t he glass only. Press the black probe against the threaded base and the red probe against the center tab on the bottom of the base. Watch the needle move from resting at the left and move quickly to 0 on the right. Change the range of the meter to R x 1. Zero the meter again for this range. Repeat the step above. Observe how the meter did not go as far to the right as before. The scale of resistance has been changed so that each number on the R scale can be read directly. In the previous step, each number represented a value that was 100 times greater. Thus, 150 really was 15,000 before. Now, 150 is just 150. Had the R x 10 scale been selected, 150 would have been 1,500. The scale selected is very important for accurate measurements. With this understanding, study the R scale. It is not linear like the other scales. Values at the left side are harder to accurately read than those on the right. Trying to read 5 ohms on the meter 90

while in the R x 100 range would look like 0. It would be much easier at the R x 1 scale instead. This is why when testing resistance, adjust the range so that the readings may be taken from the middle rather than the extreme left or right sides. Test resistance between hands. Set the meter to the highest R x value possible. Zero the meter. Loosely hold a probe in each hand and read the meter. Squeeze both probes tightly. Notice the resistance is reduced. Let go of the probes and wet your hands. Hold the probes again. Notice that the resistance is lower still. For these reasons, it is very important that the probes not touch anything other than the device under test. A device that has burned out will not show "open" on the meter when testing if your fingers provide an alternate path around the device, like when they are touching the probes. Testing round cartridge type and older style glass automotive fuses will indicate low values of resistance if the fuse is lying on a metal surface when under test. The meter indicates the resistance of the metal surface that the fuse is resting upon (providing an alternate path between the red and black probe around the fuse) instead of trying to determine resistance through the fuse. Every fuse, good or bad, will indicate "good".

How to Measure Voltage Measuring Alternating Current (AC)

Please be extra careful in doing this, 220 volts might be expected. The higher the voltage the higher the risk of electric shock. Do this with the supervision of your teacher otherwise skip this hands-on activity.

Set the meter for the highest range provided for AC Volts. Many times, the voltage to be measured has a value that is unknown. For this reason, the highest range possible is selected so that the meter circuitry and movement will not be damaged by voltage greater than expected. If the meter were set to the 50 volt range and a common electrical outlet were to be tested, the 220 volts present could irreparably damage the meter. Start high, and work downward to the lowest range that can be safely displayed. Insert the black probe in the "COM" or "-" jack.

Insert the red probe in the "V" or "+" jack. Locate the Voltage scales. There may be several Volt scales with different maximum values. The range chosen the selector knob determines which voltage scale to read. The maximum value scale should coincide with selector knob ranges. The voltage scales, unlike the Ohm scales, are linear. The scale is accurate anywhere along its length. It will of course be much easier accurately reading 24 volts on a 50 volt scale than on a 250 volt scale, where it might look like it is anywhere between 20 and 30 volts. 91

Test a common electrical outlet. Please be extra careful in doing this, 220 volts should be expected. The higher the voltage the higher the risk of electric shock. Do this with the supervision of your teacher. Press the black probe into one of the straight slots. It should be possible to let go of the black probe, as the contacts behind the face of the outlet should grip the probe, much like it does when a plug is inserted. Insert the red probe into the other straight slot. The meter should indicate a voltage very close to 210 or 230 volts. The range of the meter is important to obtain accurate measurements. This could be deadly. Whenever possible, try to connect at least one probe in such a way that it will not be required to hold both while making tests. Some meters have accessories that include alligator clips or other types of clamps that will assist doing this. Minimizing your contact with electrical circuits drastically reduces the chances of sustaining burns or injury.

Measuring Direct Current We will be using a 1.5 battery. Introduction Voltmeters measure the voltage difference between two points touched by their leads. Material: A commercial voltmeter a 1.5 volt cell such as a AA, C or D cell. (or any kind of functional 1.5 battery) To Do and Notice Measure the voltage across one, “1.5 volt battery”.

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Measuring the voltage across a battery. Details

What voltage does the battery claim to be? (1.5 volts) Set the meter scale to measure direct current DC voltage use the first scale larger than 1.5 volts. Perhaps 2, 5, 10 or 20 volts. Hook up a bulb to a battery, measure the voltage across the bulb by touching the two leads of the meter to the two leads of the bulb.

A meter is used to measure the voltage across a bulb.

93

A closeup of the meter measuring voltage. Voltage Your answer is probably not 1.5 Volts but it should be close. The voltage across older batteries will be lower. If it isn’t see “troubleshooting” below.

Additional Activity Measure the voltage across combinations of 2 batteries. Each battery by itself will produce an increase in voltage of about 1.5 volts between its negative end and its positive end.

Batteries in series. Try batteries: in series, with the positive end of one touching the negative end of the other; in opposition, with the positive end of one touching the positive end of another; and in parallel, with both positives and negatives joined.

94

Batteries in parallel Optional. Measure other cells such as C and D cells, notice that they produce the same voltage difference between their ends as do AA cells.

Troubleshooting If the meter needle “goes the wrong way” then reverse the two meter leads, the red lead should go to the positive end of the cell&emdash; the end with the bump on it&emdash; while the black lead should go to the negative end. (And, of course, the black lead should go to the COM, or common, connection on the meter and the red lead to the V, or voltage, connection. If your answer is not between 1.4 and 1.7 volts then you are probably reading the wrong set numbers, ask your teacher for help. If they you get an answer far from 1.5 volts then try another battery Test the battery first on another meter to make sure it gives the correct voltage. If the voltage is still way off, try another meter . If your meter does not work swap connector leads with someone whose meter does work. Were your leads bad or was it the meter? What you have just done is called troubleshooting, in particular this is troubleshooting by substitution, and is one of the most useful skills an electronics technician can possess

Lesson 4/Activity 5 – Use the Right Tool for the Job Directions: Given are the set of activity and the corresponding picture. Perform them using the appropriate tools and materials. Your performance will be graded using the following criteria:

95

Activity 1. Tighten and loosen screws of different head slots using different types of screw drivers.

Images of the Activity

2. Cut different sizes of wires using side cutting and long nose pliers.

3. Practice removing insulators using side cutting and long nose pliers.

4. Use a wire stripper to remove wire insulators of different sizes of wires (solid/stranded).

96

5. Using long nose pliers practice making terminal loops.

6. Solder two pieces of electrical wire.

• Never tease your classmates while working. • Use the right tools for a specific task. • Do not use tools with a broken insulator in the handle to avoid accident. • Work with your heart and always focus on your work. • Always think that you are working with a live wire. Be extra careful. Additional Activity: Directions: Answer the following questions. • How did you find the activities? ___________________________________________________________________ ___________________________________________________________________ __________.

• What particular activity did you enjoy the most? Why? ___________________________________________________________________ ___________________________________________________________________ ___________.

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• Which activity did you find difficult? Why? ___________________________________________________________________ ___________________________________________________________________ ___________. • What activity can you now confidently do? Why? ___________________________________________________________________ ___________________________________________________________________ ___________.

D. TRANSFER

Performance1/Assessment1 – CONSTRUCTION OF SERIES CIRCUIT Sample Scoring Criteria Your performance or product will be judged based on the following criteria:    

Functionality Quality Method Speed

Criteria Functionality

5 points The circuit wasfunctional

Quality

Connections were properly secured, output was presentable

3 points The circuit was functional but intermittent. Connections were properly secured, output was not presentable.

1 point The circuit was not functioning. Connections were not properly secured, output was not presentable. 98

Method

Followed all the given procedure.

Safety work habits

No incidence of injury happened.

Time Management Finished the task on time.

Followed the instruction with one to two noted incorrect usage of tools. Noticed one incidence of injury. Finished the task after the given time.

Followed the instruction with three or more noted incorrect usage of tools. Noticed more than one incidence of injury. Unable to finish the given task.

Try building this simple series circuit Materials & Tools List Each group needs: 2 D-cell batteries 2 wide rubber bands 3 #40 light bulbs 3 light bulb holders 46 in (50.2 cm) insulated wire (gauge AWG 22) 1 switch Wire strippers or sandpaper (to remove insulation at wire ends) Side cutter Small standard screwdriver

Note: Most of the materials required for this lab can be reused in numerous other electricity activities. W hen the batteries wear out, dispose of them at a hazardous waste disposal site.

99

Introduction/Motivation Do you have Blinker Lights (Season Lights) at home? Why it is that if one light goes out on a strand of blinker lights then half of the strand or the entire strand stops working? Many newer strands of lights have more than one wire linking the lights, as a better way to string the lights together; in this case, if one bulb burns out, the rest of the lights do not go out -- only a section goes out. Do you have flashlight that required batteries? How many batteries does the flashlight needed. Why do larger flashlights require more batteries than smaller flashlights? Three AA batteries connected "in series" can provide more voltage than a single AA battery. Blinker lights and the batteries in a flashlight are similar because both are connected "in series." Electrical circuits as well as batteries can be "in series" or "in parallel." Background Procedure The current is the same throughout the circuit. The total resistance for a series circuit is the sum of the resistances of each element. From Ohm's law (I=V/R), we know that the total current is equal to the voltage divided by the total resistance. There is a voltage drop across each element in a series circuit that is equal to V=I*R, where V is the voltage of the power source, I is the total current in the circuit, and R is the resistance of the element. The sum of the voltage drops across each bulb is equal to the voltage of the power source. The total voltage for batteries linked in series is the sum of the voltages of each battery. Engineers use switches placed in series to control p ractically any circuit they make. Just think — most of your electronics have an on/off switch! Before the Activity Assemble all the materials. Cut enough wire for each group: two 6 in (7.6 cm) pi eces, one 10 in (25 cm) piece, and one 4 in (10 cm) piece. You may also want to remove the insulation from the ends of the wires (step 1, below). 100

With the Students Using wire strippers or sandpaper, remove ½ in (1.3 cm) of the insulation from the ends of each piece of wire. Using masking tape, connect two batteries in series. The positive terminal of one battery should touch the negative terminal of the second battery. Connect the 10 in (25 cm) piece of wire to the positive terminal of one battery using masking tape. The other end of the 10 in wire should be connected to the terminal of one of the light bulb holders. Next, connect a 6 in (7. 6 cm) piece of wire to the negative terminal of one of the batteries using masking tape. The other end of the 6 in wire should connect to the switch. Put each light bulb in a light bulb holder. Finish constructing the series circuit using the parts you have already made, plus a second light bulb holder, the remaining 6 in (7.6 cm) wire, and the 4 in (10 cm) piece of wire (see Figure 1).

Figure 1. The activity setup: A series circuit (left) and the corresponding circuit diagram (right).

On your Series Circuit Building W orksheet, draw a circuit diagram of your circuit. Follow along on the worksheet for the rest of the activity. Close the switch. What happens to the light bulbs? Open the switch. Remove one light bulb from its base. Close the switch. What happens to the light bulb in the circuit? Open the switch. Replace the light bulb you removed and remove the other light bulb from its base. Close the switch. What happens to the light bulb in the circuit? Open the switch. Make a circuit with three bulbs in series. Close the switch. What happened to the brightness of the bulbs as you increased the number of bulbs in the series circuit? 101

Use one team's circuit and observe what happens to the brightness of the bulbs as you add a third battery in series. What happens? Safety Issues Be very careful when using the sharp wire strippers and wire cutters. Do not play with the insulated wire; they might poke or cut you or another student.

Troubleshooting Tips There must be good electrical contact between all the circuit components. If you have difficulty getting the circuit to work, be sure to double check all t he connections. Do not connect more than four D-cells in series for this activity. Four D-cell batteries connected in series totals 6.0 Volts, and most #40 light bulbs can only sustain 6.3 Volts through the filament. Assessment Pre-Activity Assessment Prediction: Before conducting the activity, ask students to predict: How many batteries do you think it will take to light the two light bulbs? Activity Embedded Assessment Worksheet: At the beginning of the activity, hand out the Series Circuit Building Worksheets. Have students follow along, first diagramming the series circuit they have constructed, then filling in answers as they work through the activity; review their answers to gauge their mastery of the subject.

Post-Activity Assessment Remember the equation, I = V ÷ R. This is called Ohm's law. Explain that I = current = flow of electric charge through the circuit (this remains constant through a closed circuit), V = voltage = batteries used, and R = resistance = bulbs used. Explain your series circuits in terms of Ohm's law. Write the correct letter I, V or R next to the symbols in their circuit drawings. What happens to the current (I) when we add another battery (V)? What happens to the current (I) when we add another light bulb (R)? What happens to the current (I) when we have an open switch? What might be the use or application of the circuit ? Is it used in a house? Or a toy? Or an appliance? Include the circuit diagram and a short explanation of how the circuit works. 102

Additional Activity Use a multimeter to measure the voltage across two batteries in series. How does the voltage compare to the voltage of one battery? Use a multimeter to determine the voltage across each light bulb and the current in each bulb. Find the resistance of the light bulb using R=V/I. Then, use the multimeter to determine the voltage across two bulbs in series and the current in the bulbs. Find the resistance of this load using R=V/I. Compare the resistance of one bulb to the resistance of two bulbs in series. Compare the voltage across one bulb to the voltage across the battery terminals. (Photocopy/copy on your notebook/journal) Name: ____________________Grade & Sec:_____________ Date: ____________ Series Circuit Building Worksheet

1. Draw a circuit diagram of the series circuit you constructed with two batteries (taped together as one), two light bulbs and a switch, if used.

2. What happened in the series circuit (above) when you closed the switch?

3. What happened in the series circuit when you removed one light bulb?

4. What happened in the series circuit when you removed the other light bulb?

5. What happened in the series circuit when you added a third bulb in series?

6. What happened to the brightness of bulbs if you increased the number of bulbs in a series circuit? 7. What happened to the brightness of the bulbs when a third battery was added in series? 8. How is opening the switch like removing a light bulb from the circuit?

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Additional activity for series circuit (Photocopy or copy on your notebook) Name: ____________________Grade & Sec:_____________ Date: ____________ Problem Solving Worksheet

1. Draw a circuit diagram for a circuit that has one battery and two light bulbs connected in series.

2. For the above circuit, what is the total resistance if one bulb has a resistance of 2 Ω and a second bulb has a resistance of 3? The total resistance for two bulbs in series is equal to the sum of their resistances.

3. For a circuit that has one battery and two light bulbs connected in series, one bulb has a resistance of 1 Ω, and the total resistance of the circuit is 6 Ω. What is the resistance of the second light bulb?

4. If a circuit has two 1.5 V batteries in series, what is the voltage across the two batteries?

5. If a circuit has two 1.5 V batteries in series and one 3 Ω light bulb, what is the current in the circuit?

Use this equation to find the total resistance of the circuit: 21totalRRR+= Use the Ohm’s law equation: RVI=

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Performance2/Assessment 2 – CONTRUCTION OF PARALLEL CIRCUIT Sample Scoring Criteria Your performance or product will be judged based on the following criteria:    

Functionality Quality Method Speed

Criteria Functionality

5 points The circuit was functional

Quality

Connections were properly secured, output was presentable

Method

Followed all the given procedure.

Safety work habits

No incidence of injury happened.

Time Management Finished the task on time.

3 points The circuit was functional but intermittent. Connections were properly secured, output was not presentable. Followed the instruction with one to two noted incorrect usage of tools. Noticed one incidence of injury. Finished the task after the given time.

1 point The circuit was not functioning. Connections were not properly secured, output was not presentable. Followed the instruction with three or more noted incorrect usage of tools. Noticed more than one incidence of injury. Unable to finish the given task.

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Materials and Tools List Each group needs: 2 D-cell batteries 3 #40 bulbs 3 bulb holders 48 in (122 cm) of insulated wire (gauge AWG 22) (available at hardware stores) 1 store-bought light switch or 1 paperclip and 2 thumbtacks 1 paper towel tube or Masking/Packaging Tape 4 Bulbs and Batteries Parallel Circuit Activity W orksheets 4 Electric Power Math Worksheets or Parallel Circuit Problem Solving Worksheets For the entire class to share: Rubber bands Wire strippers or sandpaper (to remove insulation at wire ends) Side cutters Screwdriver

Note: Many of the materials required for this activity can be reused in numerous other electricity activities. W hen the batteries wear out, dispose of them at a hazardous waste disposal site.

Introduction/Motivation When designing the electrical system for cars, trucks or SUVs, electrical engineers design the wiring system so the brake lights and headlights are connected in parallel. That way, when one of the bulbs in a headlight or brake light burns out the other headlight or brake light remains illuminated. Headlights and brake lights are only a few examples of the many devices that engineers connect in parallel. Engineers use parallel circuits often to make sure that if one circuit part breaks, the rest of the circuit continues to work. Procedure

igure 1. A parallel circuit (left), and its corresponding circuit diagram (right). 106

Background — Parallel Circuits Since each device connects across the same two nodes (a point where two wires intersect), the voltage across each device is the same. The total resistance for a parallel circuit is less than the resistance of any one branch. From Ohm's law (I = V / R), the total current is equal to the voltage divided by the total resistance. The total current divides among parallel branches. Branches with lower resistances have higher current, while branches with higher resistances have lower current. The total current is equal to the sum of the currents in the branches. The total voltage for identical batteries connected in parallel is the same as the voltage across any one battery. Engineers connect things in parallel so that if one circuit part breaks the rest of the circuit still works.

Before the Activity Assemble all the materials. If you conducted the series circuit activity, reuse the wires, light bulbs, light bulb holders and batteries from that activity. Cut four 6 in (15 cm) pieces, two 10 in (25 cm) pieces, and one 4 in (10 cm) pieces for each team. Predict how many batteries it will take to light the two light bulbs and record their prediction on the Activity Worksheet. Use the wire strippers or sandpaper to remove about 1/2 in (1.3 cm) of the insulation from the ends of each wire piece. Make a battery holder. Using masking tape, connect two D-cell batteries in series. The positive terminal of one battery should be touching the negative terminal of the second battery. Cut a paper towel holder to fit the leng th of the two batteries. Place the two batteries in the paper towel tube. Connect a 10-in wire t o the positive terminal of one battery and another 10-in wire to the negative terminal of the second battery. Construct a circuit using the two batteries in series, a switch, and two light bulb holders and light bulbs in parallel (see Figure 2). Close the switch. What happens? (Answer: Both bulbs light up.)

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igure 2. A parallel circuit with two light bulbs. Open the switch and remove one of the light bulbs from its holder. Close the switch. What happens? (Answer: The bulb remaining in the circuit lights up. See Figure 3.)

igure 3. A parallel circuit with one light bulb removed, and one light bulb remaining in the circuit.

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Open the switch and replace the light bulb you removed. Now remove the other light bulb. Close the switch. What happens? Open the switch. Replace the bulb you removed and add a third light bulb in parallel with the first two. Close the switch to test the circuit. What happens? What happens to the brightness of the bulbs as you add a fourth bulb in parallel? Use the knowledge you have gained about parallel circuits to complete the Parallel Circuit Activity Worksheet and the Parallel Activity Problem Solving Worksheet. Attachments Parallel Circuit Activity Worksheet Parallel Circuit Activity Worksheet Answers Parallel Circuit Activity Problem Solving Worksheet Parallel Circuit Activity Problem Solving Answers

Safety Issues

Do not to play with the light bulbs or holders. If either of these items break, they can cause injury. Do not to play with the insulated wire; you may cut or poke yourself or others.

Troubleshooting Tips There must be good electrical contact between all the circuit components. If you have difficulty getting the circuit to work, check all the connections. Assessment Pre-Activity Assessment (For regular high school) Human Diagram: Ask for three volunteers. Assign one volunteer to be the "battery" and two as 'light bulbs." (It may help to draw the appropriate symbols on pieces of paper and tape them to their shirts.) Have the students physically portray a series circuit by holding hands in a circle. Then have the students portray a parallel circuit by having the light bulbs and battery stand facing one direction with their arms touching the elbows of the person in front of them. Prediction: Hand out the Activity Worksheets before the activity begins. Have students predict how many batteries they think it will take to light the two light bulbs, and record their prediction on the worksheet.

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Activity Embedded Assessment Worksheet: Get the Worksheets before the activity begins. Create a diagram of the parallel circuit that you have constructed, then filling in answers as they work through the activity. Post-Activity Assessment (For regular high school) Roundtable: Have the class form into teams of 3-5 students each. Have the students on each team make a list of objects that might have parallel circuits in them by each person taking turns writing down ideas. Students pass the list around the group until all ideas are exhausted. Have teams read aloud the answers and write them on the board. (Possible items: Lights in a house, appliances, computers, toys, CD players, cell phones, etc.) Make It Fun with Boggle!: Repeat the same activity as above, except when the teams read aloud their answers and write them on the board, ask if any other teams came up with the same idea. If any other teams have the same answer on their sheet, all teams have to cross that answer out on their list. The team that ends up with the most "unique" ideas, wins!

Activity Extensions Use one team's circuit and insert a third battery in parallel. Use a multimeter to measure the voltage across the two batteries. How does it compare to the voltage of one D-cell battery? Use a multimeter to determine the voltage and current across a single light bulb, using a simple circuit with one light bulb. Use these values to find the resistance of the light bulb using Ohm's law R = V / I. Next, use the multimeter to determine the voltage across two bulbs in parallel and the current in the circuit. Find the resistance of this load using R = V / I. Compare the resistance of one bulb to the resistance of two bulbs in parallel. Compare the current in one bulb to the current in the circuit.

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(Photocopy or copy on your notebook)

Name: ________________________________________ Date: _______________ Parallel Circuit Activity Worksheet

1. How many batteries do you think it will take to light up two light bulbs?

2. Draw a circuit diagram of the circuit you constructed with one battery, a switch and two light bulbs in parallel.

3. What happened to the parallel circuit (above) when you closed the switch?

4. What happened to the parallel circuit (above) when you removed one of the light bulbs?

5. What happened to the parallel circuit (above) when you removed the other light bulb?

6. What happened to the brightness of the first two bulbs when you added a third bulb in parallel?

7. What happened to the brightness of the bulbs when you added bulbs in a parallel circuit?

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Performance3/Assessment 3. SOLDERING TECHNIQUE USING COPPER WIRE

Construct a figure or image using copper wire applying proper soldering techniques. Directions: Perform the soldering techniques using the following: Materials: 1 meter Solid wire #22 awg ½ meter Soldering lead ¼ sheet Pad paper   

Tools: Soldering Iron (30-40 watts) Long Nose Pliers Side Cutting Pliers Soldering Stand    

Procedure in Soldering: 

Clean the tip of the soldering iron or gun using sand paper, file or knife.



Remove the insulator of the wire.



Clean the bare wire conductor using sand paper.



Divide the wire into ten (10) equal lengths.



Arrange the wire in ¼ sheet of paper. (The illustration below will be your reference.)



Connect the plug of the soldering iron to the power source.



After two to three minutes tin the tip of soldering with the soldering lead.



•

Heat the intersection of wires for few seconds. Apply appropriate amount of soldering lead on the free heated surface of the wire and not directly to the tip of the soldering iron.

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

Allow the melted solder to flow evenly around the joint surface.



Remove the tip of soldering iron and allow it to cool naturally.

  

Check the soldered joints it should be smooth and shiny. Reheat the joints if necessary to avoid cold soldered joints. Finish all intersection following the same procedures.

You have to solder all wire intersections

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Note: Your output will be judged using the given Criteria: • Quality • Distance • Speed Sample Scoring Criteria – should be in past tense – cannot edit as it is a picture

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Performance4/Assessment 4. SOLDERING COMPONENTS ON PCB Materials: 1 universal PCB (Ready Made) 20 assorted resistors 1 meter soldering lead, 60:40 1 soldering iron 1 extension cord 220 V Procedure: 1. Mount all the resistors on the PCB board as shown below. Follow the correct mounting procedure.

2. One at a time, solder the resistor properly. 3. Use at least 5 seconds in soldering every joint to avoid damage on PCB foil. 4. Do not leave solder nuggets that can provide nuggets or bridges between foils. 5. Be sure to cut all excess wire to avoid short circuits.

Self-check: 1. What is the composition of the most commonly used soldering lead? 2. How do you clean or tin a tip when soldering? 3. Why must the material or joint to be soldered be cleaned very well before soldering?

Note: Your output will be judged using the given Criteria: • Quality • Component Placement • Speed

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Sample Scoring Criteria Criteria 5 points Quality All solders were smooth, shiny and with no sharp edges. Component Placement

All resistors were placed properly.

Speed

Finished the task on or before the given time.

3 points One to three solders were rough, not shiny and had sharp edges. One to three resistors were improperly placed. Finished the task after the given time.

1 point Four or more were rough, not shiny and had sharp edges Four or more resistors were improperly placed. Unable to finish the task.

Performance 5/Assessment 5. ASTABLE MULTIVIBRATOR USING TRANSISTOR (Make use of the sample project plan) Mounting and soldering components on PCB Procedure in mounting and soldering components on printed circuit board. 1. Carefully check the ready-made PCB against the diagram and inspect for any microscopic shorts or open paths. Do the remedial steps, if necessary. 2. Insert the two 33k,1/4 resistors as indicated in the diagram. 3. Insert the two electrolytic capacitors in the PCB as shown in the diagram. 4. Mount the two NPN transistor in the PCB taking into consideration the proper orientation of their electrodes(Emitter, base, and collector). 5. Mount the two jumbo LEDs (Light Emitting Diodes) to the place intended for in the PCB. 6. Remove the insulation of a 4-inch #22 black stranded hook-up wire with at least 1/8 of an inch on both ends. Insert the uninsulated part at one end for the negative supply. 116

7. Do the same as in step no. 6 using the red hook-up wire for the positive supply. 8. Let your work be checked by your teacher before making any soldering job. 9. Solder the connections of your work following the procedure of proper soldering technique. Direction: Let your teacher guide you in mounting and soldering the components of the blinker circuit on PCB applying proper soldering techniques.

Preparing a Project Plan You might be wondering why there are several projects which are not completed. Well, there are several reasons why this happens. It might be out of budget or not properly planned. So, this lesson will help you accomplish the desired and quality project. A plan is essential before undertaking any project because it serves as your guide in accomplishing an activity. It will give you an idea on what is to be done, how much to spend and what procedures to undertake. A well prepared project plan saves time and cost of materials. Below is a sample project plan of an extension cord. This format can also be used in preparing a plan for other projects in the future. 117

Sample Project Plan Name of Student:_______________________ Year & Section:______________ Date Started: _______________ Date Finished: ______________ I - Name of Project: ________________________ II- Purpose: •

to acquire knowledge and develop skills on how to assemble (project).

•

assemble a quality and marketable (project),

•

observe safety measures.

III- Drawing/Diagram: IV- Materials Needed: Qty

Unit

Description

Unit Cost

Total Cost

TOTAL COST OF MATERIALS

=

+ cost of labor (approximately 20 % to 30 % of cost of materials)

+

SELLING COST

=

V- Tools and Equipment Needed:

VI- Procedure in assembling (project): • •

Prepare the plan. Gather all necessary materials, tools and equipment needed.

VII- Criteria for Assessment:

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Sample Scoring Rubrics Criteria 5 points Quality All solders were smooth, shiny and with no sharp edges. Component Placement

All resistors were placed properly.

Speed

Finished the task on or before the given time.

3 points One to three solders were rough, not shiny and had sharp edges. One to three resistors were improperly placed. Finished the task after the given time.

1 point Four or more were rough, not shiny and had sharp edges Four or more resistors were improperly placed. Unable to finish the task.

VIII- Remarks: ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ Suggested Activity: Directions: In your own opinion, is project planning important in assuring quality, profitability and marketability of extension cord? Why? ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________

Always bear in mind the importance of a well-prepared project plan.

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VI. SUMMARY With the common competencies introduced in this module the students should have gained basic knowledge about Consumer Electronics Servicing, as well as basic skills in using different hand tools & equipment, reading of VOM, interpreting some components schematic diagram and also being aware of the importance of occupational health and safety. With the incorporation of Personal Entrepreneurial Competencies and Market & Environment Analysis a student may also see the advantages and many opportunities of being a skilled Electronics Technician.

VII.

GLOSSARY

AC voltage - a voltage in which the polarity alternates Accidental - occurring unexpectedly, unintentionally, or by chance. Ampere - basic unit of current Anode - a positive electrode of semiconductor device Bridge Rectifier - a circuit using four diodes to provide full-wave rectification. Burns - damage to the skin caused by exposure to fire or excessive heat by the range value Circuit - an arrangement of one or more complete paths of electron flow. Color Code - set of colors used to indicate value of a component Current - the rate of transfer of electricity from one point to another Cuts - break in the skin inflicted by sharp objects Desoldering - a process of unsoldering unwanted parts or components in the circuit Direct current - an electric current that flows in one direction Discrete components- separated or individual components Electric shock - effect on body on sudden discharge of electricity Electrostatic discharge - releasing of the electrical charges produced by the human Fire extinguisher - an equipment of chemicals intended to terminate or extinguish fire. First Aid Kit – medicine for initial treatment of any wounds inflicted to a person Flammable - tending to burn quickly Full Wave Rectifier - the rectifier that makes use of the full ac wave in both positive Fuse - a device in the current path that melts or breaks when there is overload in the circuit. Gloves - covering of leather, cotton, silk, etc for the h and. Goggle - spectacles for protecting eyes from glare, dust, and other pollutants. Half Wave Rectifier - a diode rectifier that converts AC to pulsating DC by Hazard - something causing danger Injury - damage or harm caused to the structure or function of the body. Malfunction - not in normal functionality Mask - covering for concealing and protecting the face Occupational health - pertaining to wellness of an individual with reference to an occupation Output - terminal at which a component, circuit or piece of equipment delivers 120

PCB - insulating board containing conductive tracks for circuit connections Power Supply - electrical equipment used to deliver either AC or DC voltage Primary Coil - first winding of a transformer winding that is connected to the source Range multiplier - a portion in the ohmmeter where the actual reading is multiplied Rectification - process that converts alternating current to direct current Rectifier - diode circuit that converts AC to pulsating DC Resistance - the opposition to the flow of electrons Resistor color coding - a scheme to determine the value of resistors by color bands Risk - exposure to something unpleasant Safety practices - set of rules or procedure intended for a safe execution Soldering - a process of joining two metals caused by heat Soldering technique - a right process in which the solder (lead) is being applied Sort - arrange things according to kinds, types, or classification Standardize - to make things in same features or level in quality or achievement Systematize - arrange methodically things in a laboratory Technician - a person skilled in mechanical or industrial techniques. Tool kit - a small bag or box equipped with hand tools Troubleshooting - identifying and repairing faults in equipment Volt - basic unit of voltage Voltmeter - an instrument that measures the amount of electromotive force

VIII.

REFERENCES

TESDA-Technical Education and Skills Development Authority. Consumer Electronics Servicing II. Retrieved October 8, 2012 from http://www.tesda.gov.ph/inc/files/Consumer%20Electronics%20Servicing%20NC%2 0II.doc NDT Education Resource Center. Electricity. Retrieved October 9, 2012 from http://www.ndt-ed.org/EducationResources/HighSchool/Electricity/hs_elec_index.htm

YouTube. Electricity 101 Episode 1. Retrieved October 9, 2012 from http://www.youtube.com/watch?v=WbNjrKtR0BY&feature=related

Electronics Project Design. Basic Electronic Tools Used to Assemble Electronic Projects and Electronic Kits. Retrieved October 22, 2012 http://www.electronicsproject-design.com/ElectronicTools.html IndiaMART. Classification of Hand Tools. Retrieved October 22, 2012 from http://sourcing.indiamart.com/engineering/articles/classification-hand-tools/

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Wikipedia. Multimeter. Retrieved October 23, 2012 from http://en.wikipedia.org/wiki/Multimeter Wikipedia. Ocupational Safety and Health. Retrieved October 10, 2012 from http://en.wikipedia.org/wiki/Occupational_safety_and_health#Service_sector Power Up. Types of Circuit. Retrieved October 24, 2012 http://powerup.ukpowernetworks.co.uk/over-11/circuits/types-of-circuit.aspx Learn About Electronics. Home Portal. Retrieved October 24, 2012 http://www.learn-about-electronics.com Science With Me. Learn About Electricity. Retrieved October 24, 2012 http://sciencewithme.com/learn-about-electricity/

Bibliography All brand names, trademarks, trade names, and WebPages used in this Learning Material (LM) are owned by their respective holders. The Publisher and the Authors do not represent nor claim ownership over them. While every effort and precaution have been made to ensure complete and accurate information with reference to the materials presented in this LM, the Publisher and Authors can neither guarantee nor be held legally responsible for any mistake in printing or faulty instructions in the LM. The Publishers and Authors appreciate receiving notice of any errors or misprints.

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Ia- Electronics Lm Grade 7 & 8 p&d

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