LMECE132

LABORATORY MANUAL ECE 132 BASIC ELECTRICAL AND ELECTRONICS ENGINEERING LABORATORY

1

LIST OF PRACTICALS

S.No.

Title of experiment

Page No.

1

AC circuits (Familiarization of resistors, capacitor and inductor)

03-13

2

House wiring (Wiring of different lamp control, stair casing circuits, assembly and wiring of fluorescent tube light)

14-16

3

4 5

Distribution board (To make a single phase main distortion board with five outgoing outgoing circuits for light load and fan load including including main switch and and fuses fuses)) PN Junction Diode (To study the VI characteristics of PN junction diode and Zener diode) voltage regulator (Implementation of voltage regulator using Zener diode)

17-17

18-20 21-23

6

Rectifier (Implementation of half wave and full rectifier using diodes and thyristors thyristors on bread board and and also on Pspice)

24-26

7

Resonance (To verify series and parallel resonance in AC circuits)

27-30

8

Bipolar junction transistor (To study the VI characteristics of Bipolar junction transistor)

31-36

9

DC Motor (Direction control of DC motor)

37-37

10

Thyristor (S ( Study tth he VI VI ch characteristics of of a Th Thyristor)

38-39

2

LIST OF PRACTICALS

S.No.

Title of experiment

Page No.

1

AC circuits (Familiarization of resistors, capacitor and inductor)

03-13

2

House wiring (Wiring of different lamp control, stair casing circuits, assembly and wiring of fluorescent tube light)

14-16

3

4 5

Distribution board (To make a single phase main distortion board with five outgoing outgoing circuits for light load and fan load including including main switch and and fuses fuses)) PN Junction Diode (To study the VI characteristics of PN junction diode and Zener diode) voltage regulator (Implementation of voltage regulator using Zener diode)

17-17

18-20 21-23

6

Rectifier (Implementation of half wave and full rectifier using diodes and thyristors thyristors on bread board and and also on Pspice)

24-26

7


27-30

8


31-36

9

DC Motor (Direction control of DC motor)

37-37

10

Thyristor (S ( Study tth he VI VI ch characteristics of of a Th Thyristor)

38-39

2

EXPERIMENT NO. 1 AC circuits: Familiarization of resistors, capacitor nd inductor

Familiarization of resistors: Learning Objectives:    

Explain the function of and uniit of resist resistors ors Measure the value of a resisto r Measure the tolerance of a re istor Explain the types of resistors

Resistors:   

Oppose the flow of current (electrons) Resistance is measured in hm 1000 Ohm resistor is show as 1 k Ohm and 1000 K Ohm resistor is shown as 1 M Ohm

Types of resistors:  

Fixed Variable

Fixed resistors: Carbon film, metal film, wire wou d resistors (value of resistor is specified and cannot be changed) Variable resistors: Semi fixed completely variable, potentiomete tentiometerr (can be changed changed by rotating the iper) Reading value of fixed resistors: Resistors are color coded as they a e too small for the value to be written on the . There are 4 or 5 bands of color. Value of a resistor is decoded from these bands of color.

3

Reading value: Step 1:

If your resistor has four color ban s, turn the resistor so that the gold or silver band is on the right hand side or the end with more bands sh uld point left. Step 2: The first band is now on the left h nd side. This represents the first digit. Base on the color make a note of the digit. In this case- 4 band its ‘5’ and for 5 band its ‘2’. Step 3: The second band represents the s cond digit. The colors represents the same numbers as did the first digit. In this case- 4 band its ‘6’ an for 5 band its ‘3’. Step 4: The third band divulgues how ma y zeros to add/divide to the first two numbe rs – for a 4 band resistor. In this case- 4 band its ‘4’ zeros to be added. So value is 560K. Step 5: The third band denotes the 3 rd digi – for a 5 band resistor. In this case -5 band its ‘7’. So the value of the 5 band resistor is 237 Ohms as its ultiplier digit is ‘0’. Tolerance: The last band denotes the tolerance . So the value of the 4 band resistor it is +/- 1%. 4

   

Tolerance of a resistor is al o an important property to consider A 100 Ohm resistor with a 10 % tolerance can mean its value can be a y fixed value between 90 to 110 Ohms A 120 Ohm resistor with a 10 % tolerance can mean its value can be an fixed value between 108 and 132 Ohms So there is some overlap between 100 Ohm and 120 Ohm resistance in t rms of its limits.

Mnemonic to remember:

5

Carbon film resistors: Most general purpose, cheap resistor   Tolerance of resistance val e is usually +/- 5 %  Power ratings of 1/8 W, 1/4 W, and 1/2 W are usually used  Con: Tend to be electricall noisy

Metal film resistor:  Used when higher toleranc is needed, ie more value  They have about +/- 0.05 tolerance

Wire wound resistors:  A wire wound resistor is made of metal resistance wire, and bec use of this they can be manufactured to precise values  Also, high wattage resistors can be made by thick wire material  Have very high power ratings

Familiarization of Capacitor:

Learning Objectives: 1. 2. 3. 4.

Provides definition of capa itance and name its unit Explain how capacitor can e constructed to give a particular value of capacitance Explain why capacitor has aximum working voltage Determine experimentally the energy stored in the capacitor 6

5. Identify the value and type of capacitor 6. Determine the polarity of terminals What is a capacitor? A capacitor is an electronic compo ent which has a wide range of uses in vario s circuits due to their ability to store charge.

There are several types of capacito s which will vary in its construction but all way

ill function in the similar

Construction of capacitor: The basic construction of all cap citor is that it consists of two parallel met al plates separated by an insulating medium (dielectric). A insulator is a medium which is non- con ucting i.e. it shows high resistance to the path of letting to e lectric current flow through it.

7

For a capacitor the simplest type o capacitor used is air. Other types are oil or paper. Real capacitors are made by taking thin strips of met al foil and the appropriate dielectric mediu and sandwiching them. Capacitor achieves large area (th s large capacitance) by taking a large are of foil sandwiching the insulating medium and rolling the in form of a cylinder. Capacitor is so called because of its capacity to store energy. Capacitor are marke by a value indicating its capacitance i.e. th ir ability to store charge. Capacitance can be thought of as t e electrical capacity of the body. It is measu ed in Farads. Maximum working voltage: If the voltage across the capacitor plates is too high the insulator between the lates fails to insulate and charge passes from one plate to an ther. Capacitors are usually marked with the working voltage to avoid this situation. A good thumb rule i s that never place a voltage to the capacitor hich exceed two third of its maximum voltage especially in alternating current circuits. Function of capacitor: Consider a circuit set up i.e the cap acitor is connected in series with the ammeter and the switch is closed. The ammeter will show 1. 2. 3. 4.

Steady state reading A reading of zero Flip back and forth Flip on one side and come ack to zero.

Now let us extend this by using a g alvanometer on both sides of the capacitor and using a t o way switch If the switch is connected to ‘p’ then 1. 2. 3. 4.

Neither moves Both flick briefly to left Both flick briefly to right They flick briefly in opposi e directions

Now if the switch is connected to t e ‘o’ terminal: 1. 2. 3. 4.

Neither moves Both flick briefly to left Both flick briefly to right They flick briefly in opposi e directions

If instead of first moving it to ‘p’ i it’s moved to ‘o’ then it might be the possibilities as mentioned above.

8

From the behavior of the ammeter eedle it suggests that the current first flows i n one way and then it flows in the other direction when t e switch is moved from ‘p’ to ‘o’ So this suggests that 1. 2. 3. 4.

Equal amount of current flows off from one plate to the other More charge flows of from plate A onto B More charge flows of from plate B onto A No charge flows at all

Charging and discharging of cap citor: We can say that capacitor is charge d when connected to P and discharged when connected to terminal O Charging: The plate of the capacitor that is co nnected to the negative terminal of the batter y accepts electrons that the battery is producing. The plate of the capacitor that is connected to the positive terminal of the battery loses electrons to the battery. Once it is charged, the capacitor has the same voltage as that of the battery. Let us connect a battery a light bul and a capacitor in series. What are the possibilities that are about to happen? 1. The bulb will glow as long as the battery is connected 2. It will never glow 3. It will first glow and then dimming of slowly and then finally turns off If we then remove the battery and replace it with a wire, current will flow one p ate of the capacitor to the other. The bulb will glow initially nd then dim as the capacitor discharges, until it is completely out. A static description of a capacitor ehavior is understood by the expression Q = CV where Q is the total charg , C signifies how big the capacitor is and V i s the voltage across it. The dynamic description i.e. the on e which changes with time is given by the e uation. I = dV/dt This is just time derivative of static description, ‘C’ is the constant with respect to time and ‘ ’ is the rate at which charge flows. This essentially shows that the big er the current the faster the capacitor’s voltage changes. Analogy: Think of capacitor as a tub that ca n hold charge. A tub of large diameter (C), holds a lot of water (Q) for a given height (V). If we fill the tub with a thin straw ( small I) then water level –V9

will rise slowly. If we use a large pipe (large V) then water level will rise f ster. Similar for draining (discharging) tub. Of course a tub f larger diameter takes longer to fill than a t b of smaller diameter. Classification of Capacitors: 

Polarized: They have a positive and negative electrode. o Electrolytic o Tantalum o Super



Un-Polarized: They don’t have a positive and negative electrode indication Ceramic o Multilayer ceramic o Polystyrene film o Polyester film o Polypropylene o Mica o

Electrolytic capacitor: Electrolytic capacitors are polariz d and they must be connected the correct way round. It is easy to find the value of electrolytic capacitors because they are clearly printed with their capacitance and voltage rating. Tantalum capacitors: Tantalum bead capacitors are pola ized and have low voltage ratings like electrolytic capacitors. Usually, the ‘+’ symbol is used to show the positive component lead. Modern tantalum bead capacitors are printed with their capacitance, voltage an polarity in full. However older ones use a color-code system which ha two stripes (for the two digits) and s spot of color for the number of zer s to give the value in F. Un-Polarized capacitors - small alues upto 1 F:

10

Un-Polarized capacitors – Numb r code:

Un-Polarized capacitors – Color ode:

11

Familiarization of inductor: Learning Objectives:  

Explain function of inductor Explain the factors influencing inductance

Function of an inductor:



The function of a value is to control the amount of fluid that flows through a pipe.



In an electric circuit, the re istor is used to control the amount of current that flows through a conductor.



Another device that controls the current is the inductor:

However unlike the resistor that a fects the current uniformly at all times, the inductor only affects cu rrents when they are changing in value. Similarity with capacitor:    

Rate of change of voltage in a capacitor depends upon the current through it Rate of change of current in an inductor depends upon the voltage applied across it. Like capacitive current, inductive current is not simply proportional to voltage. Unlike the situation in a re sistor, the power associated with inductive current (V times I) is not turned into heat but is stored as energy in the inductor’s magnetic field.

V = L*dI/dt, Where, L is the induc ance and is measured in henry.  

Putting a voltage across an inductor causes the current to rise as a ramp. 1 volt across 1 henry produ ed a current that increases at 1 amp per second

Structure of an Inductor: It consists of a wire wound as a c il around a core. The core may consist of air filled hollow tube or solid material.

12

Inductance: The amount of inductance in henri s a coil has, is determined b y the following actors:

Inductive Kick: An inductor is capable of producin g a momentary voltage that is much higher than the voltage of the pow r source that supplied the current to create its magnetic field. This tem orary voltage is called an inductive kick.

Example of applications of induct ive devices to provide an inductive kick is a combustion engine igni tion system that creates the spark across the gap of the spark plug.

Result: The basic fundamentals of passive elements have been studied. Learning outcome: To be written by students in 50-70 words.

13

EXPERIMENT NO. 2

Wiring of different lamp control, stair casing circuits, Assembly and wiring of fluorescent tube light.

To control one lamp with the help of Two way switch Material Used: Switch board, Two way switch, Lamp holder, PVC wires, Switch sheet, Casing & Capping batten, Lamp, Nail & Screw Tool used: Combination pleir, Test pen, Screw driver, Knife, Poker Learning objective: Assembly and wiring of fluorescent tube light Circuit Diagram:

Outline of Procedure:

1) Take a wooden board. 2) Fixed casing & capping on wooden board & fixed three switch board at the end of casing & capping batten two for 2 way switch & one for Lamp. 3) Fixed Lamp holder on board. 4) Connect Phase wire to lamp holder through switch. 5) Connect neutral wore directly to lamp holder. 6) Check the circuit before connecting main supply. Precautions:

1) All connection should be tight. 2) Wire should not over long. 3) After completing the job all tools must be kept at proper place. 4) Keep your mind and eyes on the job & don’t talk any one while working. 5) Tools not being used should not be scatter on working table.

Learning outcome: To be written by students in 50 to 70 words 14

Lay out of complete house wiring with batten wiring with lamp, fan, tube light. Equipment/Tool Used:

1- phase energy meter, DP main switch, fuse, neutral link, Combination pliers, screw driver, test pen, side cutting plier, and electrician knife.

Consumable Material:

PVC Wire, Screw, PVC Batten, , Lamp holder, switch sheet, switch board, Insulation tape, fuse wire, lamp, tube fitting. To practice how to make the connection of house wiring and domestic appliances.

Learning Objective:

Outline of Procedure: Fixed 1-phase energy meter, DP main switch and switch board on their on respective places. Make the connection as per circuit diagram. Connected phase wire to lamp, socket, tube light and fan through switch and connect neutral directly. Now, switch on the power supply and job will the function.

Result: 1. Analysis of the connection of domestic wiring. 2. Proper connection of lamp, tube light and fan.

Precaution: 1. Connection should be tightly done. 2. Keep your mind and eyes on the job and don’t talk any one while working. 3. Tools being used should not be allowed to scatter on working table. .

Learning Outcome: To be written by students in 50-70 words

15

Assembly and wiring of fluorescent tube light Equipment/ Tool Required:

Combination pleir, test pen, screw driver, knife, poker

Learning Objective:

To practice how to make the connection of tube light.

Reference Drg. No.

LPU/ELECT/04(b)

Circuit Diagram:

Outline of Procedure: 1) 2) 3) 4)

Result:

Make the tube light circuit as shown in circuit diagram. Connect phase wire through switch. Connect neutral wire directly to tube rod. Connect starter to two spare terminals.

Now we are familiar with making a tube light circuit


16

EXPERIMENT NO. 3

Distribution board (To make a single phase main distribution board with five outgoing circuits for light and fan load including main switch and fuses (only internal connections), W iring and testing of alarm and indicating relays, indicating lights etc.)

To prepared a distribution board with four outgoes circuit for fan and light load along with main switch and fuses Equipment/ Tool Required: DP main

Plier, Screw Driver, Test pen, Claw hammer, Poker, Knife, Energy meter,

Switch, Distribution box 4-way, MCB 6A, Neutral link.

Consumable Material:

PVC Wire, Screw, PVC Batten, Switch, Lamp holder, switch sheet, switch

board.

Learning Objective:

In this the student knows how to divide the load to different circuit.

Outline of Procedure: 1. First of all we fixed energy meter, main switch, and distribution box on wooden board and a Bus bar and neutral link fused in distribution box. 2. Now Connect Phase wire to bus bar and neutral wire to Neutral link. 3. One Phase wire taken from main bus bar and neutral wire from Neutral Link through fuse or MCB each ckt is made from pair of Phase and Neutral wire.

Result: In this system the number of ckt and Sub ckt are divided on the basis of Load to be connected to the supply.


17

EXPERIMENT NO. 4

PN Junction Diode (To study the VI characteristics of PN junction diode and Zener diode)

Plotting V-I characteristics of PN junction diode: Equipment Required: Diode D1N4002, Resistor 1 k Ὡ, Multimeter , Wires. Material Required: Bread board, connecting wires Software Required: Pspice Learning Objective: Study of characteristics of a diode. Circuit diagram:

Outline of Procedure:   



Connect the circuit as per circuit diagram. Use PSpice to obtain the i-v characteristic of the diode with model number D1N4002. Sweep the input voltage from -15 V to 15 V. When simulation is complete probe graphic window appears. Add the trace I (D1). This is the trace of the diode current versus the supply voltage Vss. We need to change the x-axis variable to V (Vd) to obtain the plot of diode current versus diode voltage. To do this from the Plot pull-down menu select X Axis Settings, click the Axis Variable button to open the variable list, and select V (Vd) to be the horizontal axis. After performing the simulation, implement the same on the bread board to draw VI characteristics of PN junction diode. 18

Ideal graph:

Plotting V-I characteristics of Zener diode: Equipment Required: Zener Diode D1N750, Resistor 1 k Ὡ, Multimeter . Material Required: Bread board, connecting wires Software Required: Pspice Learning Objective: Study of characteristics of a Zener diode. Circuit diagram:

19


Construct the above schematic and label the output node as V out. Select the setup from the analysis menu; click the DC Sweep dialog button. The DC sweep dialog box appears. For the Sweep variable type select the voltage source, and set its name to V1. Using the sweep type linear, set the starting value to 0, end value to 20 and increment to 0.05. When simulation is complete probe graphic window appears. From the Plot pull-down menu select X Axis Settings, click the Axis Variable button to open the variable list, and select V (Vout) to be the horizontal axis. Ideal graph:

Scope of result to be reported: Observe the V-I Curves of PN and Zener diode in PSPICE window. Cautions: Connect circuit very carefully with all components from proper Library.

Result: In this, we studied the characteristics of PN junction and Zener diode. Learning Outcome: To be written by students in 50-70 words

20

EXPERIMENT NO. 5

Voltage regulator (Implementation of voltage regulator using Zener diode)

Voltage regulator:

Learning Objective: To know about voltage regulation

21


22

RESULT- In this, we studied ho

Zener diode acts as voltage regulator.

Precautions: Connect circuit very c refully with all connections tight and clear. Do not short circuit +ve and - ve terminals of supply at any point in circuit. Learning Outcome: To be wri ten by students in 50-70 words.

23

EXPERIMENT NO. 6

Rectifier (Implementation of half wave and full wave rectifier using diodes on bread board and also on Pspice)

Half wave rectifier: Learning Objectives: To recognize a half-wave rectified sinusoidal voltage. To understand the term ‘mean value’ as applied to a rectified waveform. To understand the effect of a reservoir capacitor upon the rectified waveform and its mean value Apparatus: Diode, Wires, Power supply, resistor, capacitor. Simple Half-Wave Rectification

Circuit diagram:

Outline of Procedure:    



Switch on the oscilloscope and the sinusoidal supply. With the oscilloscope d.c. coupled adjust the time-base and t he Y amplifier sensitivity to obtain a steady trace of about 4cm vertical and 5ms/cm horizontal. Measure and record time T and peak voltage V pk : Sketch the waveform and label it to show the periods when the diode is conducting and those when it is not. Time T depends upon the frequency of your power supply. Confirm this. V pk should be very nearly equal to the peak voltage of the alternating supply 24

Output waveforms:

Full wave rectifier: Circuit diagram:

25

Outline of Procedure:   

Switch on the sinusoida supply. Measure and record time mean value of output voltage indicated on t he voltmeter Vm. Compare the mean value of output voltage indicated on the voltmete those obtained in the Half-Wave rectif cation.

Output waveforms:

Result:

Rectification of Halfwave and ullwave using diodes have been studied. Precautions: Connect circuit very c refully with all connections tight and clear. Do not short circuit +ve and - ve terminals of supply at any point in circuit.

Learning outcome: To be writ en by students in 50-70 words.

26

EXPERIMENT NO. 7


Series resonance: Appartaus Required-

Equipment

Range

Quantity

Signal generator

0-1 MHz

1

Voltmeter

0-10V

3

Ammeter

0-10mA

1

Learning Objective: Resonance in AC circuits Circuit Diagram-

Outline of Procedure: 1. Set up the circuit as shown in circuit diagram 2. Set input voltage =5V using signal generator and vary the frequency from 0-1 MHz in regular steps. 3. Note down the corresponding output voltage and current. 4. Plot the following graph a. Current v/s frequencies b. Voltage v/s frequencies 5. To measure the resonance frequency:

27

a. Plot the graph current v/s frequencies b. Draw a horizontal line, which intersects the curve at 1/sqrt(2) times the maximum current reading c.

Lower intersected point and upper intersected point are respectively called lower cut off frequency and upper cut off frequency on frequency axis

BANDWIDTH:

BW=f2-f1 BW=ω0/Q ωn=√ω1ω2 SELECTIVITY:

S=1/Q S=R/ω0L Model graph:

Tabulation:

Frequency (Hz)

Output Circuit(mA)

28

Parallel resonance: Equipment Required-

Equipment

Range

Quantity

Signal Generator

0-1 MHz

1

Voltmeter Ammeter

Circuit Diagram-

Outline of Procedure: 1. Set up the circuit as shown in fig 2. Set input voltage =5V using signal generator and vary the frequency from 0-1 MHz in regular steps 3. Note down the corresponding output voltage and current 4. Plot the following graph: Impedance v/s frequency 5. To measure the resonance frequency:

a. Plot the graph Impedance v/s frequency b. Draw a horizontal line, which intersects the curve at 1/sqrt(2) times the maximum impedance reading c.

Lower intersected point and upper intersected point are respectively called lower cut off frequency and upper cut off frequency on frequency axis

QUALITY FACTOR:

Q0=R/ω0L=R√(C/L) 29

BANDWIDTH & SELECTIVITY-

BW=f2-f1 SELECTIVITY=BW/f0=(f2-f1)/f0 Model graph:

Tabulation-

Vi=5V Frequency (Hz)

Current (mA)

Z=Vi/I

Result:

Series and parallel resonance in AC circuit have been studied. Precautions: Connect circuit very c refully with all connections tight and clear. Do not short circuit +ve and - ve terminals of supply at any point in circuit. Learning Outcome: To be wri tten by students in 50-70 words

30

EXPERIMENT NO. 8


CB configuration:

Learning Objective:- To plot the transistor characteristics of CB configuration. THEORY:

In this configuration the base is made common to both the input and out. The emitter is given the input and the output is taken across the collector. The current gain of this configuration is less than unity. The voltage gain of CB configuration is high. Due to the high voltage gain, the power gain is also high. In CB configuration, Base is common to both input and output. In CB configuration the input characteristics relate IE and VEB for a constant VCB. Initially let VCB = 0 then the input junction is equivalent to a forward biased diode and the characteristics resembles that of a diode. Where VCB = +VI (volts) due to early effect IE increases and so the characteristics shifts to the left. The output characteristics relate IC and VCB for a constant IE. Initially increased IC also increases. proportionality. Though increase in VCB remains a constant for all values of VCB once it levels off.

31

Outline of Procedure: Input characteristics:

It is the curve between emitter current IE and emitter-base voltage VBE at constant collectorbase voltage VCB. 1. Connect the circuit as per the circuit diagram. 2. Set VCE=5V, vary VBE in steps of 0.1V and note down the corresponding IB. Repeat the above procedure for 10V, 15V. 3. Plot the graph VBE Vs IB for a constant VCE. Output characteristics:

It is the curve between collector current IC and collector-base voltage VCB at constant emitter current IE. 1. Connect the circuit as per the circuit diagram. 2. Set Ib=20 mA, vary Vce in steps of 1 V and note down the corresponding Ic.repeat the above procedure for 40 mA,80 mA etc.. 3. Plot the graph VCE Vs IC for a constant IB. 4. Find the h parameters .

32

33

Results:

Fill in the observed response in the following table and design the characteri stics on its basis. Learning Outcome: To be wri tten by students in 50-70 words CE configuration:

Learning Objective:- To plot the transistor characteristics of CE configura ion.

Outline of procedure: Input characteristics: 1. Connect the circuit as per the circuit diagram. 2. Set VCE ,vary VBE in reg lar interval of steps and note down the co rresponding IB reading. Repeat the above p rocedure for different values of VCE. 3. Plot the graph: VBE Vs IB for a constant VCE. 34

Output characteristics: 1. Connect the circuit as per the circuit diagram. 2. Set IB, Vary VCE in regul r interval of steps and note down the corr sponding IC reading. Repeat the above p rocedure for different values of IB. 3. Plot the graph: VCE Vs IC for a constant IB.

35

Model graph:

Result: The transistor char cteristics of a Common Emitter (CE) co figuration were plotted. Learning Outcome: To be w itten by students in 50-70 words

36

EXPERIMENT NO. 9

DC motor (Realization of the Direction control for DC motor circuit)

Direction control of DC motor: Equipment Required: Wires, Multiple Power Supply & multimeter. Material Required: Resistor (10K, 2.2 K -2 each), Diodes (IN4007-5), Transistor (instead of TIP31 use BC 548) and DC motor (12V). Learning Objective: Direction control of DC motor using transistors. Outline of Procedure:  Connect circuit as per as the circuit diagram. Operate switches S1 and S2 to direction control of DC motor. Circuit Diagram:

Scope of result to be reported: Observe the direction of rotation of motor as we turn on the switches S1 and S2 alternately. Precautions: Connect circuit very carefully with all connections tight and clear. Do not short circuit +ve and - ve terminals of supply at any point in circuit. Learning outcome: To be written by students in 50-70 words. 37

EXPERIMENT NO. 10

Thyristor (Study the VI characteris ics of a thyristor)

VI characteristics of a Thyrist r: Apparatus required: SCR – TY604, power supplies, watt ge resistors, ammeter, voltmeter. Learning Objective: To study the VI characteristics of a Thyristor Circuit Diagram:

Outline of Procedure: 

Connections are made as show in the circuit diagram.



The value of gate current Ig, is set to convenient value by adjusting VGG



By varying the anode – cathode supply voltage VAA gradually in step by step, note down the corresponding values of VAK and IA. Note down VAK and IA at the instant of firing of SC R and after firing (by reducing the voltmeter ranges and in creasing the ammeter ranges) then increase the supply voltage VAA. Note down corresponding values of VAK and IA



The point at which SCR fires, gives the values of break over voltage VBO



A graph of VAK vs IA is to be plotted



The ON state resistance can be calculated from the graph by using a formula



The gate supply voltage VGG is o be switched off



Observe the ammeter reading by reducing the anode-cathode supply voltage V A. The point at which the ammeter reading suddenly goe to zero gives the value of holding current IH.



Steps no. 2 to 8 are repeated for another value of the gate current IG.

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LMECE132

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