Part 1 1. Which of the following materials refers to as a recipient of impurity element? a. phosphorous b. antimony c. arsenic d. gallium 2. What is the overall electrical charge of the P material in a semiconductor? a. some negative value b. some positive value c. depending upon the balance of electrons, it will be positive or negative d. zero 3. What provides you with information concerning the voltage current relationship of a PN junction diode? a. the color coded bands on the diode b. the printed information on the diode c. the characteristic curve graph of the diode d. the body color of the diode 4. An electronic semiconductor behaves as ____ at absolute zero temperature a. a variable resistor b. a conductor c. a super conductor d. an insulator 5. Electron current flows from: a. neutral to negative b. positive to negative c. neutral to rest d. negative to positive 6. In the PN junction, which of the following actions will increase the number of majority carriers and increase current flow in a forward biased condition? a. decreasing battery voltage b. increasing the size of the P material c. decreasing the size of the P material d. increasing battery voltage 7. ____ refers to the majority carrier in an N type semiconductor a. hole b. positive ion c. negative ion d. electron 8. The conductivity of P type and N type semiconductor materials depends on: a. the doping level b. the electron number c. the nucleus weight d. the mass of the nucleus 9. A p type semiconductor has a shortage of which of the following? a. neutrons b. electrons c. holes d. doping 10. What type of diode has green, blue, and orange bands? a. 1N572 b. 1N563 c. 1N463 d. 1N663 11. An intrinsic semiconductor has some holes in it at room temperature. What causes these holes? a. doping b. free electrons c. thermal energy d. valence electrons 12. What causes the process called junction recombination to occur when N and P materials are joined together? a. the development of an electrostatic field on each side of the junction b. the diffusion of electrons and holes moving across the junction into the two materials c. the loss of electrons to the depletion region d. the generation of heat which causes the electrons to bombard the holes at the junction 13. What two elements widely used in semiconductor devices exhibit both metallic an non metallic characteristics? a. galena and germanium b. silicon and gold c. galena and bismuth d. silicon and germanium 14. Assume the valence electron is removed from a copper atom. The net change of the atom becomes a. 0 b. +1 c. -1 d. +4 15. After the junction recombination process has reached equilibrium, what is the area that surrounds the junction called? a. depletion region b. anode c. electrostatic field d. free ion space 16. A device whose operation depends upon only on type of current carrier is called a/an ___ device. a. bidirectional b. bipolar c. unipolar d. bilateral 17. The ideal diode is usually adequate when a. troubleshooting b. doing precise calculations c. the source voltage is low d. the load resistance is low 18. If we increase the electrostatic reverse bias on a PN junction of semiconductor material, we will reach a point where the reverse current in the diode increases dramatically. This is called: a. forward breakdown b. depletion breakdown c. zener breakdown d. reverse junction breakdown 19. The relationship between current and voltage is ____ proportional. a. linearly b. logarithmically c. exponentially d. inversely 20. A voltage applied to a PN junction so that it reduces the junction barrier ad aids current flow is what type of bias? a. forward b. reverse c. indirect d. direct 21. An atom that has gained an electron is called a ____. a. negative ion b. positive ion c. ion d. cation 22. The majority carriers in an n type semiconductor are a. holes b. conduction electrons c. valence electrons d. protons 23. In a forward biased PN junction, when an electron leaves the negative terminal of the battery and enters the N material, it becomes what type of carrier? a. minority b. signal c. loop d. majority 24. Semi conductors which doped with either N or P types impurities are called _______. a. intrinsic b. P typec. Extrinsic d. N-type 25. Holes in an n type semiconductor are a. minority carriers that are thermally produced b. majority carriers that are thermally produced c. minority carriers that are produced by doping d. majority carriers that are produced by doping 26. The depletion region is created by
a. ionization b. diffusion c. recombination d. A, B, and C 27. What will happen if a voltage is applied to an intrinsic semi conductor at room temperature? a. most of the electrons and holes move towards the negative terminal b. most of the electrons and holes move towards the positive terminal c. the electrons will tend to move towards the negative terminal and the holes toward the positive terminal d. the electrons will tend to move towards the positive terminal and the holes towards the negative terminal 28. The particles that make up the lattice in ionic crystal a. molecules b. ions c. atoms c. neutrons 29. A PN junction is formed by a. ionization b. the boundary of a P type and an N type material c. the recombination of electrons and holes d. the collision of a proton and neutron 30. ____ is an orderly pattern of combined silicon atoms. a. covalent bond b. valence orbit c. semiconductor d. crystal 31. One of the prime dangers to the semiconductor diode is heat. Excessive current generated by heat which eventually destroys a diode is called a. thermal runaway b. thermionic emission c. junction overload d. thermoplastic action 32. Silicon atoms combine into an orderly pattern called a a. covalent bond b. crystal c. semiconductor d. valence orbit 33. Where does the widest gap between valence band and the conduction band? a. conductor b. vacuum tube c. insulator d. semiconductor 34. Recombination is when a. a crystal is formed b. a positive and a negative ion bond together c. an electron falls into a hole d. a valence electron becomes a conduction electron 35. The avalanche breakdown in a semiconductor takes place at any one of the following conditions. a. when reverse bias exceeds the limiting value b. when forward current exceeds the limiting value c. when potential barrier is reduced to zero d. when forward bias exceeds the limiting value 36. In a semiconductor crystal, the atoms are held together by a. force of attraction b. the interaction of valence electrons c. covalent bonds d. answer A, B and C 37. As you make a front to back ratio check of a diode with an ohmmeter, your first measurement (forward) is a low resistance reading, and your second measurement (reverse) is also a low reading. What should be your evaluation of the diode? a. it is shorted b. it is leaky c. it is open d. it is good 38. Reverse breakdown voltage for a diode is typically greater than ___. a. 0V b. 0.7 V c. 10 V d. 50 V 39. Electrons are never found in which of the following bands? a. energy band b. forbidden band c. valence band d. conduction band 40. An atom consist of a. one nucleus and only one electron b. one nucleus and one or more electrons c. protons, electrons, and neutrons d. answer B or C 41. the majority carriers in an n-type semiconductor a. dope b. holes c. quanta d. electrons 42. Each valence electron in an intrinsic semiconductor establishes a a. covalent bond b. free electron c. hole d. recombination 43. What determines whether a substance is an insulator, semiconductor, or conductor? a. the separation between the conduction and valence bands b. the separation between the forbidden band and the energy gap c. the separation between the conduction and forbidden bands d. the separation between the valence and forbidden bands 44. Type of impurity in n type semiconductor like arsenic and antimony a. covalent b. pentavalent c. quadvalent d. trivalent 45. The n-type portion of the depletion region is devoid of ____. a. majority b. holes c. electron hole pairs d. ions 46. When the insulators are compared to the semiconductor, (a) which one requires the least energy to move an electron and (b) from which point in the energy level does the electron leave in its travel to the conduction band? a. (a) semiconductor (b) forbidden band b. (a) insulator (b) forbidden band c. (a) semiconductor (b) valence band d. (a) insulator (b) valence band 47. Avalanche occurs in ___ diode if the bias voltage equals or exceeds the ___. a. unbiased, applied voltage b. forward biased, breakdown voltage c. reverse biased, break voltage d. forward biased, peak inverse voltage 48. The difference between an insulator and a semiconductor is a. a wider energy gap between the valence band and the conduction b. the number of free electrons c. the atomic structure d. answer A, B and C 49. In their natural state, all atoms are neutral because they have an equal number of ____. a. protons and electrons b. protons and neutrons c. neutrons and electrons d. molecules and ions 50. at room temperature an intrinsic semiconductor has
a. few free electrons and holes b. many holes c. many free electrons d. no holes 51. In semiconductor technology one of the following refers to the majority carrier in an N material a. hole b. protonc. neutron d. electron 52. The number of free electron and holes in an intrinsic semiconductor increases when the temperature a. decreases b. increases c. stays the same d. none of the above 53. What are the two types of current in an intrinsic semiconductor? a. valence electron current and hole current b. free electron current and electron hole current c. free electron current and hole current d. valence electron current and ionic current 54. the flow of valence electrons to the left means that holes are flowing to the a. left b. right c. either way d. none of the above 55. Hole current occurs when __ move from ____ to ____ creating, in effect, a movement of holes in the opposite direction. a. valence electrons, valence band, conduction band b. valence electron, hole, hole c. valence electron, conduction band, valence band d. valence electron, hole, conduction band 56. Silver is the best conductor. How many valence electrons do you think it has? a. 1 b. 4 c. 18 d. 29 57. The ___ carriers in a/an ____ semiconductor are ____ acquired by doping. a. majority, p-type, holes b. minority, n-type, free electrons c. minority, p-type, holes d. majority, n-type, holes 58. The application of a dc voltage to a diode to make it either conduct or block current. a. biasing b. doping c. recombination d. potential 59. How many electrons are there in the valence orbit of a silicon atom within a crystal? a. 1 b. 4 c. 8 d. 14 60. Which of the following describes a p-type semiconductor? a. neutral b. positively charge c. negatively charged d. has many free electrons 61. Valence electrons are a. in the closet orbit to the nucleus b. in various orbits around the nucleus c. in the most distant orbit from the nucleus d. not associated with a particular atom 62. Semiconductor ____ bond together in a ____ to form a solid material called as __. a. atoms, symmetrical pattern, crystal b. electrons, amorphous pattern, lattice c. electrons, symmetrical pattern, crystal d. atoms, amorphous pattern, glass 63. What causes the depletion layer? a. doping b. recombination c. barrier potential d. ions 64. A positive ion is formed when a. there are more holes than electrons in the outer orbit b. Two atoms bond together c. a valence electron breaks away from the atom d. an atom gains extra valence electron 65. What is the barrier potential of a silicon diode at room temperature? a. 0.3 V b. 0.7 V c. 1 V d. 2 mV per degree Celsius 66. Trivalent impurities are also called as ____. a. acceptor atomsb. donor atoms c. host atoms d. semiconductor atoms 67. When a diode is forward biased, the recombination of free electrons and holes may produce. a. heat b. light c. radiation d. all of the above 68. If a valence electrons acquires enough energy from an outside source such as heat, it can jump out of the ___ and break away from its another _______. a. conduction band, molecule b. valence band, atom c. forbidden band, ion d. energy band, proton 69. For N-type SI semiconductor materials, the Fermi level is how many eV above the edge of the valence band? a. 0.555 eV b. 0.82 eV c. 0.335 eV d. 0.265 eV 70. The reverse bias condition causes the barrier voltage to seemingly: a. decrease in level b. increase in level c. remain at the same leveld. none of these 71. For P-type SI semiconductor materials, the Fermi level is how many eV above the edge of the valence band? a. 0.555 eV b. 0.705 eV c. 0.335 eV d. 0.265 eV 72. the difference in energy between the valence and the conduction bands of a semiconductor is called ___. a. band gap b. extrinsic photoeffect c. conductivity d. energy density 73. The knee voltage of a diode is approximately equal to the a. applied voltage b. barrier potential c. breakdown voltage d. forward voltage 74. In the P-type semiconductor, what are the majority carriers? a. inactive atoms b. electrons c. inert atoms d. holes 75. The placing of an impurity on a semiconductor of the opposite impurity and fusing the two together produce what type of semiconductor junction? a. alloy junction b. intrinsic junction c. barrier junction d. grown junction 76. Each atom in a silicon crystal has a. o valence electrons because all are shared with other atoms
b. eight valence electrons because all are with other atoms c. four valence electrons d. four conduction electrons 77. The maximum current permitted to flow in the forward direction in the form of non recurring pulses a. peak current b. peak forward current c. minimum forward current d. maximum surge current 78. A perfect bond at the junction of the two diode materials is important for which of the following reasons? a. it is the point at which amplifications takes place b. it is the main structural point from where the diode gets its strength c. it is the point at which rectification takes place d. all of the above 79. How much current is there through the second approximation of a silicon diode when it is reverse biased? a. 0 b. 1 mA c. 300 mA d. 1A 80. When a semiconductor is doped its conductivity tends to ____. a. decrease in the reverse ratio as the doped material b. increase c. decrease in the inverse ratio as doped material d. remain 81. Current flow in a copper wire can be compared to current flow in what type (s) of semiconductor material? a. P-type only b. all types c. n-type d. n-type and p-type 82. The depletion region is consist of a. nothing but minority carriers b. positive and negative ions c. no majority carriers d. answer B and C 83. How much forward voltages are there with the ideal diode approximation? a. 0 b. 0.7 V c. more than 0.7 V d. 1 V 84. the term bias means a. a dc voltage s applied to control the operation of a device b. the amount of current across a diode c. the ratio of majority carriers to minority carriers d. neither A, B nor C 85. The bulk resistance of 1N4001 is a. 0 b. 0.23 ohm c. 10 ohms d. 1 kohms 86. Devices that either produce light or use in their operation a. optical b. optronics c. opto electronics d. night vision 87. The only time you have to use the third approximation is when a. load resistance is low b. source voltage is high c. troubleshooting d. none of the above 88. Every known element has a. the same type of atoms b. a unique type of atom c. the same number of atoms d. several different types of atom 89. Valence band holes are ___ carriers for n type material a. negative b. majority c. minority d. conventional 90. ___ is an excess property of P type semiconductor. a. hole b. electron c. proton d. neutron 91. To forward bias a diode a. an external voltage is applied that is positive at the anode and negative at the cathode b. an external voltage applied that is negative at the anode and positive at the cathode c. an external voltage is applied that is positive at the p region and negative at the n region d. answer A and C 92. Conduction band electrons are ___ carriers for p type material. a. majority b. positive c. hole d. minority 93. When accelerating electrons collide with valence band electrons and break their covalent bonds before reaching the positive supply terminal, the resulting high value of current is called ___ current. a. avalanche b. skin effect c. dark d. diffusion 94. What happen if the grid is made more positive that the saturation point? a. no other amplification takes placeb. the tube stops conducting c. the tube elements might be damaged d. electrons are drawn to the grid and do not reach the plate 95. For a silicon diode, the value of the forward bias voltage typically a. must be greater than 0.3 V b. depends on the width of the depletion region c. depends on the concentration of majority carriers d. must be grater than 0.7 V 96. Neutrons have a/an ___ charge. a. negative b. neutral c. electronegative d. positive 97. Which of diode’s maximum ratings can be exceeded without causing damage to the PN junction? a. maximum forward current rating b. maximum reverse voltage rating c. maximum temperature rating d. none of these 98. For N type SI semiconductor materials, the Fermi level is how many eV below the edge of the conduction band? a. 0.555 eV b. 0.705 eV c. 0.335 eV d. 0.265 eV 99. What type of material is formed when trivalent material is doped with silicon or germanium? a. PN type b. N type c. N and P type d. P type 100. Of the following test, which is the most valid for checking a diode?
a. the substitution of a new diode of the questionable b. a forward and reverse resistance check using two different ohmmeter one c. a forward and reverse resistance check with an ohmmeter d. a dynamic electrical check with a diode test set Part 2. 1. The process of adding an impurity to an intrinsic semiconductor is called a. atomic modification b. doping c. recombination d. ionization 2. At absolute zero temperature an intrinsic semiconductor has a. a few free electrons b. many holes c. many free electrons d. no holes or free electrons 3. An atom has discrete bands of energy called ___ in which the ___ orbit. a. gap, electrons b. gaps, ions c. shells, electrons d. shells, ions 4. A trivalent impurity s added to silicon to create a. germanium b. an n type semiconductor c. a depletion region d. a p type semiconductor 5. A p-type semiconductor contains holes and a. positive ions b. negative ions c. pentavalent atoms d. donor atoms 6. What phenomenon in electronic does an avalanche breakdown primarily dependent? a. doping b. recombination c. collision d. ionization 7. The valence shell in a silicon atom has the number designation of a. 1 b. 0 c. 3 d. 2 8. The most widely used semiconductor material in electronic device is a. silicon b. carbon c. germanium d. copper 9. A/an _____ semiconductor material is created by adding impurity atoms that have ___ valence electrons. a. p-type, 5 b. n-type, 5 c. p-n-type, 4 d. p-type 3 10. Surface leakage current is part of the a. forward current b. forward breakdown c. reverse current d. reverse breakdown 11. When forward biased, a diode a. block current b. has a high resistance c. conducts current d. drops a large voltage 12. ____ is the procedure by which an atom is given a net charge by adding or taking away of electron. a. irradiation b. polarization c. ionization d. doping 13. After pure semiconductor material has been doped, it is called ___ semiconductor material. a. intrinsic b. amorphous crystals c. neutral d. extrinsic 14. When a voltmeter is placed across a forward biased diode, it will read a voltage approximately equal to a. the diode barrier potential b. the bias battery voltage c. the total circuit voltage d. 0 V 15. Since the primary mechanism for current flow is conduction band electrons in n-type crystals, we say that conduction band electrons are the ___ carriers in n type semiconductors. a. flow b. majority c. negative d. minority 16. The voltage where avalanche occurs is called the a. barrier potential b. depletion layer c. knee voltage d. breakdown voltage 17. Pentavalent impurities are also called as ___. a. acceptor atomsb. donor atoms c. host atoms d. semiconductor atoms 18. The reverse current consists of minority carrier current and a. avalanche current b. forward current c. surface leakage current d. zener current 19. The purpose of a pentavalent impurity is to a. increase the number of free electrons b. create minority carriers c. reduce the conductivity of silicon d. increase the number of holes 20. How much voltage is there across the second approximate of a silicon diode when it is forward biased? a. 0 V b. 0.3 V c. 0.7 V d. 1 V 21. The bonds that hold a semiconductor crystal together are called ___. a. crystallic bond b. ionic bond c. covalent bond d. Vander-Waals bond 22. The negative and positive charge symbols are assigned (in that order) to the a. proton and electron b. electron and proton c. atom and nucleus d. electron and element 23. The number of neutrons in an atom a. is always equal to the number of protons b. is always equal to the number of electrons c. may not be equal to the number of protons d. may be equal to the sum of electrons and protons 24. What is the overall charge of the N material in a semiconductor? a. some negative value b. some positive value c. depending upon the balance of electrons, it will be positive or negative d. zero 25. Each free valence electron and the resulting hole formed in a semiconductor material is known as:
a. valence electron pair b. electro hole pair c. valence band pair d. semiconductor pair 26. Applying a voltage source to pure semiconductor material results in: a. free electrons moving to the positive terminal b. electron hole pairs forming c. holes effectively moving to the negative terminal d. all of these 27. For p-type SI semiconductor materials, the Fermi level is how many eV below the edge of the conduction band? a. 0.555 eV b. 0.82 eV c. 0.335 eV d. 0.265 eV 28. The protons have a ___ charge, electrons are ___ charge, and the neutrons are ____. a. positive, negatively, uncharged b. neutral, negatively, positively charged c. negative, positively, uncharged d. positive, neutrally, negatively charged 29. Holes act like a. atoms b. crystals c. negative charges d. positive charges 30. The outermost shell or band of an atom is called the ___, and the electrons that orbit in this band are called ____. a. forbidden band, forbidden electrons b. energy gap, bound electrons c. valence band, valence electrons d. atomic band, atomic electrons 31. Doping a semiconductor with trivalent impurities results in: a. P-N-type material b. N-type material c. N-P type material d. P-type material 32. In P type doped semiconductor materials I. electrons are the minority carriers II. Holes are the minority carrier III. electrons are the majority carriers IV. Hole are the majority carriers a. I and IV b. I, II and IV c. II and III d. I, II, III and IV 33. Impurities with five or more valence electrons are also known as: a. acceptor atomsb. intrinsic atoms c. donor atoms d. all of these 34. A silicon diode is in series with 1.0 k resistor and 5 V batteries. If the anode is connected to the positive battery terminal, the cathode voltage with respect to the negative battery terminal is a. 0.7 V b. 5.7 V c. 0.3 V d. 4.3 V 35. The region beyond the valence band is called the ___ band. a. conduction b. protonc. electron d. forbidden 36. Pure forms of silicon and germanium that are not doped are called ___ semiconductors. a. amorphous crystals b. intrinsic c. extrinsic d. neutral 37. For intrinsic SI semiconductor materials, the Fermi level is how many eV above the edge of the valence band? a. 0.555 eV b. 0.705 eV c. 0.335 eV d. 0.29 eV 38. To produce a large forward current in a silicon diode, the applied voltage must be greater than a. 0 V b. 0.3 V c. 0.7 V d. 1 V 39. The area in the p-n junction that has shortage of holes and electrons a. balk region b. depletion region c. forward region d. barrier region 40. In a silicon diode the reverse current is usually a. very small b. very large c. zero d. in the break down region 41. Within a doped semiconductor material, there will be: a. more holes in P type b. an equal number of mobile and ionic charges c. more free electrons in N-type d. an equal amount of anions and electrons 42. When the reverse voltage increases from 5 to 10 V, the depletion layer a. becomes smaller b. becomes larger c. is unaffected d. breaks down 43. A process of constant loose of free electrons and then regaining them is called ____. a. induction b. ionization c. polarization d. electron gaining 44. The area close to the junction of N and P type materials formed by majority carriers crossing the junction is known as: a. the barrier region b. the semiconductor region c. the junction region d. the depletion region 45. For intrinsic Ge semiconductor materials, the Fermi level is how many eV below the edge of the conduction band? a. 0.555 eV b. 0.705 eV c. 0.335 eV d. 0.29 eV 46. it exhibits a negative temperature coefficient a. conductor b. ceramic c. semiconductor d. super conductor 47. Diffusion of free electrons across the junction of an unbiased diode produces a. forward bias b. reverse bias c. breakdown d. the depletion layer 48. The opposite charges that build up on each side of a PN junction creates the a. barrier potential b. junction voltage c. depletion voltage d. PN voltage 49. According toe the classical bohr model, the atom is viewed as having a planetary type structure with ___ orbiting at various distances around the central -__. a. electron, proton b. electrons, nucleus c. nucleus, neutron d. anions, atom 50. A forward biased PN junction requires: a. a negative voltage source connected to P material b. a positive voltage source connected to N material c. a negative voltage source connected to N material d. all of these 51. The nucleus of an atom consist of a. electrons and neutrons b. protons and electrons c. protons and neutrons d. ions and electrons 52. Protons are about ___ heavier than electrons
a. 1, 800 times b. less than thrice c. less d. twice 53. Atoms with five valence electrons are called a. trivalent materials b. intrinsic materials c. pentavalent materials d. semiconductor materials 54. A donor atom has how many valence electrons? a. 1 b. 3 c. 4 d. 5 55. Why are capacitors used as coupling components in many circuits? a. because they pass DC and block AC b. because they ass AC and block DC c. because they amplify DC and block AC d. Because they amplify AC and block DC 56. Which is the majority carrier in an N type semiconductor? a. electron b. positive ions c. negative ion d. hole 57. the number of _____ represents the ____ of the atom. a. atoms, atomic number b. electrons, atomic number c. neutrons, atomic weight d. protons, atomic number 58. The small value of direct current that flows when a semiconductor has reverse bias a. surge current b. bias current c. reverse current d. current limit 59. What process takes place within the semiconductor to cause hole flow? a. the flexing of the material b. the breaking of covalent bonds c. the splitting of atoms d. the combining of valence bands 60. In an intrinsic semiconductor a. there are no free electrons b. the free electrons are thermally produced c. there are as many electrons as there are holes d. answer B and C 61. The process of adding impurities to semiconductor materials is called as ____. a. doping b. decomposition c. ionization d. recombination 62. Rectification is the process of a. changing DC to AC b. converting electricity to magnetism c. changing AC to DC d. converting electricity to electromagnetism 63. The _____ carriers in a/an ___ semiconductor are ____ produced by thermally generated electron hole pair. a. majority, p-type, free electrons b. minority, n-type, holes c. minority, p-type, holes d. majority, n-type, free electrons 64. A material which has an equal number of electron hole pairs and conducting electrons is known as what type of semiconductor material? a. P-type b. N-type c. intrinsic d. extrinsic 65. Electrons in the outer band or shell of an element are characterized by their: a. size b. mass c. energy d. speed 66. A curve showing the relationship of diode characteristic. a. V-I characteristic curve b. V-R characteristic curve c. I-R characteristic curve d. P-VI characteristic curve 67. The merging of a free electrons and a hole is called a. covalent bonding b. lifetime c. recombination d. thermal energy 68. The nucleus of an atom is made up to a. proton and neutrons b. electrons and protons c. electrons d. protons 69. Semiconductors which are considered to be “low power” of “small signal” usually have power dissipation ratings of a. 1 watt of less b. 5 watts or less c. exactly 1 watt d. 10 watts or less 70. The atomic number of germanium is a. 32 b. 4 c. 2 d. 8 71. A/an ____ semiconductor material is created by adding impurity atoms that have ___ valence electrons. a. p-type, 5 b. n-type, 5 c. p-n type, 4 d. n-type, 3 72. Depletion region is form by ____. a. electron hole pair b. recombination c. ionization d. doping 73. If you wanted to produce a p type semiconductor, which of these would you use? a. acceptor atomsb. donor atoms c. pentavalent impurity d. silicon 74. The p type portion of the depletion region is devoid of ___. a. electrons b. holes c. electron hole pairs d. ions 75. What is the majority carrier in an N material? a. neutron b. electron c. hole d. proton 76. The electrical particles of the atom are the a. molecules and mixtures b. electrons, elements and protons c. protons and nucleus d. neutrons, electrons, and protons 77. A/an ___ is a positively charged particle in the nucleus of all atoms. a. compound b. electron c. neutron d. proton 78. If an outer orbit electron acquires sufficient energy, it can break away from its parent atom. Disassociated electrons are called ___ electrons. a. loose b. wandering c. bound d. free 79. The energy band in which free electrons exist is the a. first band b. conduction band c. second band d. valence band 80. Holes are the minority carriers in which type of semiconductor? a. extrinsic b. intrinsic c. n-type d. p-type
81. The tiny crystal of semiconductor material that glows when an electric current passes through it and are used in digital display and for indicating that power is on in electronic crystal is called ___ a. liquid crystal display b. laser beam c. light emitting diode d. photon 82. Electron holes pairs are produced by a. ionization b. thermal energy c. recombination d. doping 83. Materials whose molecules readily arrange themselves into crystal structures are held together by: a. sharing valance electrons b. full valence shells c. covalent bonding d. all of these 84. An electronic device which operates by virtue of the movement of electrons within a solid piece of semiconductor a. solid state device b. thin film c. water d. substrate 85. Suppose an intrinsic semiconductor has 1 billion free electrons at room temperature. If the temperature changes to 750C, how many holes are there? a. fewer than 1 billion b. 1 billion c. more than 1 billion d. impossible to say 86. What are normally the front to back ratio of (a) a power rectifier and (b) a signal diode? a. (a) 10:1 (b) 300:1 b. (a) 300:1 (b) 50:1 c. (a) 10:1 (b) 50:1 d. (a) 300:1 (b) 10:1 87. When diode is forward biased a. the only current is hole current b. the only current is produced by majority carriers c. the current is produced by both holes and electrons d. the only current is electron current 88. The ___ carrier in a/an ___ semiconductor are __ acquired by doping. a. majority, p type, free electrons b. minority, p type, holes c. minority, n type free electrons d. majority, n type, free electrons 89. An external voltage source is applied to a p type semiconductor. If the left end of the crystal is positive, which way do the majority carriers flow? a. left b. right c. neither d. impossible to say 90. It is composed of a series of energy levels containing the valence electrons a. conduction band b. forbidden band c. valence band d. side band 91. Which one of the following materials is the best conductor of electrons? a. aluminum b. copper c. silicon d. gold 92. Although current is blocked in reverse bias a. there is some current due to majority carrier b. there is very small current due to minority carrier c. there is an avalanche current b. answer A and B 93. In an intrinsic semiconductor, the number of free electrons a. equals the number of holes b. is greater than the number of holes c. is less than the number of holes d. none of the above 94. Process of varying resistance is photosensitive material exposed to light, such as high resistance in dark and decrease resistance with light is called ____ a. photocell b. photoconduction c. photonics d. photoemission 95. The current in a semiconductor is produced by a. holes only b. electrons only c. both electrons and holesd. negative ions 96. How many free electrons does a p type semiconductor contain? a. many b. none c. only those produced by thermal energy d. same number as holes 97. The ____ carriers in a/an _____ semiconductor are ____ produced by thermally generated electron hole pairs. a. majority, p-type , holes b. minority, n-type, free electrons c. minority, p-type, free electrons d. majority, n-type, holes 98. _____ diodes are used to change an AC voltage into DC voltage in a power supply. a. switching b. clipper c. rectifier d. clamper 99. types of impurities in p type semiconductor like boron and gallium a. covalent b. bivalent c. pentavalent d. trivalent 100. The maximum junction temperature of a power amplifier is 1500C and the maximum ambient temperature of the area it will be used in is 450C. The maximum power that this device could dissipate without overheating. a. 2.63 W b. 3.75 W c. 2.3 W d. 1.13 W Part 3. 1. A zener diode a. is used for high current rectification b. is intended to operate in forward bias c. emits light when current flow d. is intended to operate in reverse bias 2. If the filter capacitance is increase, the ripple will a. decrease b. stay the same c. increase d. none of these 3. How much voltage regulation does commercial power supply have? a. 10% and above b. within 1% c. 15% and above d. 10% 4. internally, an Optoisolator uses a. photo emitter LED b. a photodiode c. a transformer d. Ans. A & B 5. If you are checking a 60 Hz full wave bridge rectifier and observe that the output has a 60 Hz ripple
a. the filter capacitor is leaky b. the transformer secondary is shorter c. there is an open diode d. the circuit is working properly 6. An advantage of full wave rectifier over half wave rectifier a. each diode can cool off during half of each input signal b. the ripple frequency is lower c. the rectifier will conduct during both halves of the input cycle d. output voltage is lower with more ripples 7. What is true about the breakdown voltage in a zener diode? a. it decrease when current increases b. it destroys the diode c. it equals the current times the resistance d. it is approximately constant 8. The output of an Optoisolator can include a. MOSFET drivers b. phototransistors c. thyristor drivers d. all of the above 9. The cathode of zener diode in a voltage regulator is normally a. more negative than the anode b. more positive than the anode c. at + 0.7 V d. grounded 10. ____ is the output of a half wave rectifier. a. half wave rectified signal b. square wave signal c. AC signal d. sinusoidal signal 11. Which of these is the best description of a zener diode? a. it is a rectifier voltage diode b. it is a constant voltage device c. it is a constant current device d. it works in the forward region 12. the arrow in the schematic symbol for a diode points which way? a. toward the cathode b. in the direction of current flow c. towards the anode d. towards the magnetic north 13. Power supply voltage regulators can control: I. variation in the DC output voltages II. Variations in the frequency of input and output voltages III. Variations in the DC output current IV. Variations in the frequency of input and output current V. variations in the AC input voltage a. I, IV and V b. I, III and V c. II, III & IV d. III, IV and V 14. ____ limits the maximum forward current in a junction diode. a. the peak increase voltage b. the junction temperature c. the forward voltage d. the back EMF 15. The diode with a forward voltage drop of approximately 0.25 V is the a. step recovery diode b. schottky diode c. back diode d. constant current diode 16. Each diode is a FWR is forward biased and conducts for ___ of the input cycle. a. 450 b. 900 c. 1800 d. 3600 17. How many junctions are there in a semiconductor diode? a. two b. one c. none d. four 18. If a certain zener diode has a zener voltage of 3.6 V, it operates in a. avalanche breakdown b. zener breakdown c. regulated breakdown d. forward conduction 19. A common TV remote control uses which of the following as its optical transmitter? a. red LED b. IR LED c. amber LED d. green LED 20. A zener diode a. is a battery b. has a constant voltage in the breakdown region c. has a barrier potential of 1 V d. is forward biased 21. What is the process by which AC is converted to pulsating DC? a. charging b. rectification c. filtering d. clipping 22. A forward biased LED in series with a current limiting resistor and a 5-V DC source. If the LED has a forward voltage drop of 2 V, how much voltage is across the resistor? a. 1 V b. 3 V c. 5 V d. 10 V 23. What is the commonly used figure of merit for power supply? a. voltage rating b. percent of regulation c. voltage tolerance d. voltage limit 24. Determine from the following the advantages of full wave rectifier over the half wave rectifier. a. that the ripple frequency is lower b. that the diodes will conduct during both halves of the input cycle c. that there exists the lower temperature during both halves of the cycle d. each diode can cool off during halves of the input cycle 25. For a certain 12 V zener diode, a 10 mA change in zener current produces a 0.1 V changes in zener voltage. The zener impedance for these current ranges is a. 1.0 b. 100 c. 10 d. 1 26. A half ways rectifier circuit utilizing one half of an input cycle has a ripple frequency in its output equivalent to a. 60 cps b. 120 cps c. 110 cps d. 240 cps 27. The principal operating characteristics of full wave rectifier are: I. easy to filter out the ripple voltage II. Can supply large voltages and currents III. more efficient than a half wave rectifier IV. Less PIV than half wave rectifier 28. Find the ripple factor (Kr) of a sinusoidal signal with peak ripple of 4 volts on an average of 30. a. 0.0934 b. 0.013 c. 0.130 d. 0.94
29. The varactor operates like which of the following electronic components? a. capacitor b. variable inductor c. inductor d. variable capacitor 30. The voltage across the zener resistance is usually a. small b. large c. measured in volts d. subtracted from the breakdown voltage 31. One of the following items below is not one of the main components of an alternating current power supply. a. power transformer b. rectifier c. filter d. voltage regulator 32. An increase in reverse bias of a varactor will have what effect on the width of the depletion region? a. it will fluctuate b. it will increase c. it will stabilize d. it will decrease 33. The data sheet for a particular zener gives VZ = 10 V at IZT = 500 mA. ZZ for these conditions is. a. 20 b. 50 c. 10 d. unknown 34. An LED rated 1.5 V mA is to be operated from a 12 V battery. What is the required value of the current limiting resistor? a. 420 b. 4.2 c. 42 d. 4200 35. In a power supply, what percent regulation is ideal? a. 10% b. 0% c. 100% d. 98% 36. If the series resistance decrease in an unloaded zener regulator, the zener a. decrease current b. stays the same c. increases d. equals the voltage divided by the resistance 37. Which shell contains the highest energy level? a. the innermost shell b. the second shell c. the third shell d. the outer most shell 38. How much voltage regulation does an ideal regulated power supply have? a. 1% b. 100% c. 10% d. 0% 39. In the second approximation, the total voltage across the zener diode is the sum of the breakdown voltage and the voltage across the a. source b. series resistor c. zener resistance d. zener diode 40. A varactor diode exhibits a. a variable capacitance that depends on forward current b. a variable capacitance that depends on reverse voltage c. a constant capacitance over a range of reverse voltages d. a variable resistance that depends on reverse voltage 41. A circuit that converts an ac sinusoidal input voltage into a pulsating dc voltage with two output pulses occurring for each input cycle. a. multiplier b. power supply c. HWR d. FWR 42. Which breakdown theory explains the action that takes place in a heavily doped PN junction with a reverse bias above 5 volts? a. zener effect b. valence band gap crossing c. avalanche breakdown d. energy band effect 43. A typical value of reverse breakdown voltage for a PN junction is a. 0V b. 0.3 V c. 0.7 V d. 100 V 44. The PN junction will conduct heavily a. when it is reverse biased b. when the P material is connected to the positive side of the power supply and the N material is connected to the negative side of the power supply c. when the N material is connected to the positive side of the power supply and the P material is connected to the negative side of the power supply d. when there is no power supply connected 45. This is an electronic device which provides an automatic change in resistance at any current variation to maintain a constant voltage drop, or keeping the voltage output regardless of load current variations. a. power supply b. voltage amplifier c. voltage regulator d. voltage transformer 46. For typical operation, you need to use reverse bias with a a. zener diode b. photodiode c. varactor d. all of the above 47. What is the range of voltage rating available in zener diode? a. 2.4 volts to 200 volts b. 1.2 volts to 7 volts c. 3 volts to 2000 volts d. 1.2 to 5.6 volts 48. What are the two basic types of full wave rectifier? a. Armstrong and Wien bridge b. Hartley and center tapped c. bridge and Wien bridge d. bridge and center tapped 49. Information supplied by manufacturers on the different types of diode? a. diode data b. diode specification c. diode characteristic d. diode information 50. To isolate an output circuit from an input circuit, which is the device to use? a. back diode b. optocoupler c. Seven segment indicator d. tunnel diode 51. Refers to a special type of diode which is capable of both amplification and oscillation a. zener diode b. point contact diode c. junction diode d. tunnel diode 52. The peak output voltage of a center tapped FWR is approximately ____ of the total peak secondary voltage less ____ diode drop. a. ½, two b. ½, one c. 2x, two d. 2x, one 53. An LED a. emits light when forward biased b. emits light when reverse biased c. acts as a variable resistance d. senses light when reverse biased 54. The load voltage is approximately constant when a zener diode is
a. forward biased b. reverse biased c. operating in the breakdown region d. unbiased 55. The purpose of an amperite regulator a. voltage regulation b. load regulation c. current regulation d. source regulation 56. In a loaded zener regulation, which is the largest current? a. series current b. zener current c. load d. none of these current 57. What type of bias is required for an LED to produce luminescence? a. reverse bias b. zero bias c. inductive bias d. forward bias 58. Compared to a visible red LED, an infrared LED a. produces light with longer wavelength b. produces light when reverse wavelength c. produces light with shorter wavelengths d. produces only one color of light 59. A blown fuse in a power supply is most likely the result of a. an open diode b. an open transformer secondary coil c. an open filter capacitor d. a shorted diode 60. What are the two main categories of semiconductor diodes? a. junction and point contact b. vacuum and point contact c. electrolytic and point contact d. electrolytic and junction 61. At some potential, as you increase the reverse bias voltage on a PN junction, the reverse current increases very rapidly. What electronic term is given to this voltage potential? a. forward bias b. thermal runwayc. reverse bias d. breakdown voltage 62. Which of the following value of ripple factor represent the best filter? a. 121% b. 111% c. 101% d. 91% 63. Why is a diode placed across the coil portion of a relay? a. to protect the relay against incorrect polarity b. to speed up the switching c. to protect the relay from high voltage transients when magnetic field collapses d. to increase the current flow 64. What is the “tunneling phenomenon” within the zener diode? a. an action that removes all the electrons from the conduction band energy level b. an action where the majority carrier tunnel across the junction to form the current that occurs at breakdown c. an action where the minority carriers tunnel across the junction to form the current that occurs at breakdown d. an action that separates the condition band and the valence band by a large gap 65. If the load resistance decreases in a zener regulator, the zener current a. decreases b. stays the same c. increases d. equals the source voltage divided by the series resistance 66. ___ is a type of linear voltage used in applications where the load on the unregulated voltage source must be kept constant. a. a series regulator b. a shunt regulator c. a constant current source d. a shunt current source 67. The PIV for each diode in a bridge rectifier is approximately ___ that required for an equivalent center tapped configuration and is equal to the ___ plus one diode drop. a. ½, peak output voltage b. ½, peak secondary voltage c. 2x, peak output voltage d. 2x, peak secondary voltage 68. What type of bias opposes the PN junction barrier? a. NO bias b. reverse bias c. direct bias d. forward bia 69. Positive and negative output voltage waveforms can be developed from the same transformer secondary a. using a center tapped transformer and a half wave rectifier circuit b. using a transformer without a center tap and a full wave rectifier circuit c. using a center tapped transformer, a full wave bridge rectifier, and a center tapped load resistor d. all of the above 70. What is the circuit that adds a dc level to an ac voltage using a diode and a capacitor? a. chopper b. clipper c. clamper d. limiter 71. What happens to a zener diode that has a reverse bias slightly higher than the breakdown voltage? a. zener acts like a short circuit b. zener acts like an open circuit c. zener conduction does not change d. zener cuts off 72. Why is the zener diode an ideal voltage regulator? a. it uses an unlimited number of carriers b. the voltage across the diode remains almost constant after breakdown c. operating in the breakdown region does not harm it d. it compensates for low supply voltage 73. The internal resistance of a photodiode a. increase with light intensity when forward biased b. decrease with light intensity when forward biased c. increase with light intensity when reverse biased d. decrease with light intensity when forward biased 74. If the load resistance decreases in a zener regulator, the series current a. decreases b. stays the same c. increases d. equals the source voltage divided by the series resistance 75. The measured dc output of a power supply is 14 V. the ripple is of triangular shape and is measured as 0.4 VPP. Find the % ripple for this configuration.
a. 8.2% b. 0.82%c. 2.86% d. 1.65% 76. A diode that has a negative resistance characteristics is the a. tunnel diode b. laser diode c. schottky diode d. hot carrier diode 77. What determines whether a solid material will act as a conductor, a semiconductor, or an insulator? a. the energy level of the valence band b. the energy difference across the forbidden gap c. the actual construction of the valence electrons d. the energy level of the conductor band 78. In comparing a conductor and an insulator, what is the relative dimension of the forbidden gap of (a) the conductor and (b) the insulator? a. (a) narrow (b) wide b. (a) wide (b) narrow c. (a) narrow (b) narrow d. (a) wide (a) wide 79. When the source voltage increases in a zener regulator, which of these currents remains approximately constant? a. zener current b. series current c. laud current d. total current 80. the most popular style of diode is known as: a. the press fit amount b. the radial lead c. the axial lead d. the stud amount 81. An infrared LED is optically coupled to a phtodiode. When the LED is turned off, the reading on an ammeter is series with the reverse biased photodiode will a. increase b. not change c. fluctuate d. decrease 82. If the zener diode in a zener regulator is connected with the wrong polarity, the load voltage will be closest to. a. 0.7 V b. 10 V c. 14V d. 18 V 83. In the construction of the tunnel diode, what is the ratio of impurity atoms to semiconductor atoms? a. 100,000: 10,000 b. 1,000:10,000,000 c. 10,000:100,000 d. 10,000:1000 84. the unique design feature of a zener diode needed for its operation is the: a. forward bias breakdown mode b. forward bias conduction mode c. reverse bias conduction mode d. reverse bias breakdown mode 85. A dc power supply typically consist of the following I. filter II clipper III. Transformer IV. Rectifier V. regulator VI. Chopper a. II, III, IV and VI b. III, IV, V and VI c. I, III, IV, and V d. I, IV, V and VI 86. What happens to the capacitance of a varactor diode as the reverse bias is increased? a. increases b. it remains the same c. it decreases d. A or B is possible 87. At high frequencies, ordinary diodes don’t work properly because of a. forward bias b. reverse bias c. breakdown d. charge storage 88. In the series regulator circuit is connected: a. in series with the load b. in series with the input c. in parallel with the input and in series with the load d. in series with both the input and the load 89. The capacitance of a varactor diode increases when the reverse voltage across it a. decreases b. increases c. breaks down d. stores charges 90. The reverse current in a zener diode measures as a: a. almost maximum value b. high value c. minimum value d. low value 91. Break down does not destroy a zener diode provided the zener current is less than the a. breakdown voltage b. zener test current c. maximum zener current rating d. barrier potential 92. To protect a power supply from an excessive load demand you could install: I. a fuse or circuit breaker II. A series regulator with current limiting III. a transformer IV. A series regulator a. I and IV b. I, II and IV c. II, III and IV d. I, III and IV 93. A zener diodes maximum current rating is determined principally bu its a. maximum voltage value b. maximum power dissipation c. maximum current value d. all of these 94. IN electronic circuits, how is the varactor used? a. as an amplifier b. as a balancing device c. as a rectifier d. as a tuning device 95. To display the digit 8 in a seven segment indicator a. C must be lighted b. G must be off c. F must be on d. all segments must be on 96. An optocoupler is used in circuits principally because: a. it is expensive b. it couples optical energy c. it provides a high degree of electrical isolation d. it includes both a LED and a phototransistor 97. A zener diode rated as having a negative temperature coefficient means that: a. the breakdown voltage increases with temperature decreases b. the breakdown voltage could be between 4 and 5 volts c. the breakdown voltage rating is usually below 4 volts d. all of these 98. Regulation of the output voltage over a range of input voltages is called a. line regulation b. load regulation c. voltage regulation d. output regulation
99. What is the maximum voltage allowed to appear across the diode in reverse bias? a. threshold voltage b. PIV c. knee voltage d. zener voltage 100. Regulation of the output voltage over a range of load currents is called a. line regulation b. load regulation c. voltage regulation d. input regulation Part 4. 1. with a half wave rectified voltage across the load resistor, load current flows for what part of a cycle? a. 0 degrees b. 90 degrees c. 180 degrees d. 360 degrees 2. The average value of a half wave rectified voltage with a peak value of 200 V is a. 127.3 V b. 141 V c. 0 V d. 63.7 V 3. The diode in a HWR is forward biased and conductors for ___ of the input cycle. a. 450 b. 900 c. 1800 d. 3600 4. What device is usually used as a stable reference voltage in a linear voltage regulator? a. a zener diode b. a tunnel diode c. An SCR d. a varactor diode 5. Any temperature sensitive diode especially a zener diode, can be changed into a temperature compensated diode by: a. connecting an opposite temperature coefficient diode in series with forward biasing b. connecter an opposite temperature coefficient diode in series with reverse biasing c. connecting an opposite temperature coefficient diode in parallel with forward biasing d. connecting an opposite temperature coefficient diode in parallel with reverse biasing 6. When a 60 Hz sinusoidal voltage is applied to the input of a half wave rectifier the output frequency is a. 60 Hz b. 120 Hz c. 0 Hz d. 30 Hz 7. It is a heavily doped PN junction that exhibits negative resistance over part of its range of operation. a. zener diode b. SCR c. varactor d. tunnel diode 8. What is the PIV rating or each diode in a center tapped FW rectifier? a. twice the peak secondary voltage b. equals to he peak output voltage c. twice the peak output voltage d. one half the peak secondary voltage 9. ____ is a special type diode often used in RF switches, attenuators and various types phase shifting devices. a. junction diode b. PIN diode c. varactor diode d. tunnel diode 10. Line voltage may be form 105 Vrms to 125rms in a half wave rectifier. With a 5:1 step down transformer, the maximum peak load voltage is closest to a. 21 V b. 25 V c. 29.6 V d. 35.4 V 11. A properly operating zener diode can be used to: a. regulate a voltage b. compensate for power line fluctuations c. correct for load resistance changes d. all of these 12. Which is a common use for point contact diode? a. as a constant current source b. as a constant voltage source c. as an RF detector d. as a high voltage rectifier 13. The voltage out of a bridge rectifier is a a. half wave signal b. full wave signal c. bridge rectified signal d. sine wave 14. Under what condition will a diode conduct? a. when it is forward biased b. when it is reverse biased c. at all times d. when it is amplifying 15. In order ot perform voltage regulation using a zener diode, what other circuit component is required. a. an unregulated power supply b. a series resistor c. a regulated DC load d. all of these 16. What is the peak load voltage in a full wave rectifier if the secondary voltage is 20 V rms? a. 0V b. 0.7 V c. 14.1 Vd. 28.3 V 17. Which is the principal characteristic of a varactor diode? a. it has a very high PIV b. it has a negative resistance region c. its internal capacitance varies with the applied voltage d. it has a constant voltage under conditions of varying current 18. The peak value of the input to a half wave rectifier is 10 V. the approximate peak value of the output is a. 10.7 V b. 6.3 V c. 10 V d. 3.18 V 19. Refers to the important characteristic of a three terminal regulator a. maximum and minimum input voltage, maximum output current and voltage b. maximum and minimum input voltage, minimum output current and maximum output voltage c. Maximum and minimum input voltage, minimum output current and maximum output voltage d. maximum and minimum input voltage, minimum output current and voltage 20. In testing a zener diode with a digital multimeter, what test can be performed? a. forward resistance test b. continuity test c. reverse resistance test d. all of these 21. Find the normal operating voltage and current of light emitting diode. a. 60 volts and 20 mA b. 5 volts and 50 mA c. 0.7 volts and 60 mA d. 1.7 volts and 20 mA 22. PIN diode acts like a ____ when ____ and ____ when____ a. capacitor, reverse biased, variable resistor, forward biased b. transistor, forward biased, variable capacitor, reverse biased c. variable capacitor, reverse biased, fixed resistor, forward biased
d. variable resistor, forward biased, transistor, reverse biased 23. Avalanche breakdown is primarily dependent on the phenomenon of a. doping b. collision c. recombination d. ionization 24. the average value of a full wave rectified voltage with a peak value of 75 V is a. 37.5 V b. 23.9 V c. 53 V d. 47.8 V 25. Which is the principal characteristic of a zener diode? a. a negative resistance region b. an internal capacitance that varies with applied voltage c. a constant voltage under conditions of varying current d. a constant current under conditions of varying voltage 26. The symbol for a photodiode includes: a. a bar for the cathode b. two inward facing arrows c. an arrow for the anode d. all of these 27. How does junction diodes rated? a. maximum reverse current and PIV b. maximum forward current and PIV c. maximum forward current and capacitance d. maximum reverse current and capacitance 28. We want a peak load voltage of 40 V out of bridge rectifier. What is the approximate rms value of secondary voltage? a. 0 V b. 14.4 V c. 28.3 Vd. 56.6 V 29. In order to simplify the circuit, in analysis and computation the diode is normally assumed as ____. a. zero b. ideal c. imaginary d. infinite 30. The basic purposes of an electronic power supply include: a. converting AC line power to DC b. isolating the circuit from the AC voltage source c. supplying the required values of voltage and current d. all of these 31. ____ is the forward voltage drop of a LED a. 3 V b. 0.30 V c. 1.5 V d. 0.15 V 32. The color and intensity of the light emitted by a LED depends on: a. the value of the current flow b. the semiconductor material used c. the color of the plastic case d. all of these 33. If a power supply produces 20 V with no load and 15 V under full load, what is the percent regulation? a. 33% b. 3.3% c. 75% d. 25% 34. Zener diodes are used in two different ways to control voltage, these are called: a. input and output regulation b. open and closed circuit regulation c. line or input and load regulation d. minimum and maximum current regulation 35. The output frequency of a full wave rectifier (FWR) is ___ the input frequency. a. equals to b. twice c. half d. 3x 36. ____ is the process off converting AC input to DC output a. radiation b. attenuation c. rectification d. variation 37. A photodiode is being operated in the ___ mode when it acts like a battery whose value is dependent upon the amount of light striking the PN junction a. photoemissive b. photoconductive c. photovoltaic d. electroluminescence 38. The rectifier circuit used in an AC power supply must: I. convert from 120 Hz to 60 Hz frequency II. Convert incoming AC to DC III. supply the required DC voltage and DC current levels IV. Handle the voltage formed by the transformer secondary V. convert from 60 Hz to 120 Hz frequency a. I, IV and V b. I, III and V c. II, III and IV d. III, IV and V 39. When a 60 Hz sinusoidal voltage is applied to the input of a full wave rectifier, the output frequency is a. 60 Hz b. 120 Hz c. 240 Hz d. 0 Hz 40. When the conductivity of a PN junction diode changes with varying light energy, it is being operated in the ____ mode. a. photoconductive b. photovoltaic c. photoemissive d. electroluminescence 41. With a full wave rectified voltage across the load resistor, load current flows for what part of a cycle? a. 0 degrees b. 90 degrees c. 180 degrees d. 360 degrees 42. The total secondary voltage in a center tapped full wave rectifier is 125 rms. Neglecting the diode drop, the rms output voltage is a. 117 V b. 100 V c. 62.5 Vd. 125 V 43. The semiconductor sandwich in the PIN diode stands for a. p type, intrinsic, n type b. p-type, infinite, negative c. positive, infinite, n type d. positive, intrinsic, negative 44. What is the peak load voltage out of a bridge rectifier for a secondary voltage of 15 V rms? (Use second approximation). a.9.2 V b. 15 V c. 19.8 Vd. 24. 3 V 45. When the peak output is 100 v, the PIV for each diode in a center tapped full wave rectifier is (neglecting the diode drop) a. 100 V b. 141 V c. 200 V d. 50 V 46. In a tunnel diode, in the region between peak voltage and valley voltage, the voltage is increasing while the current is decreasing. This apparent violation of Ohm’s law defines a property called ___ resistance. a. reverse b. positive c. negative d. inverse 47. The main advantage of the half wave rectifier is that it: a. generates ripple frequency equal to that of the AC input b. operates only over half of the AC input c. is simple and inexpensive to build d. requires only a single diode
48. How do you determine if diode is defective? a. diode resistance is either very low or very high on either direction b. high current b. very low current d. high voltage 49. The LED when used in a working circuit must include: a. a protective series resistor to limit current flow b. a forward bias voltage above the barrier potential c. a sufficient current flow to cause light d. all of these 50. An external voltage applied to a junction reduces its barrier and aids current flow through the junction. a. reverse bias b. external bias c. junction bias d. forward bias 51. If the frequency is 60 Hz, the output frequency of a half wave rectifier is a. 30 Hz b. 60 Hz c. 120 Hz d. 240 Hz 52. What type of PN diode is formed by using a fine metal and a section of n-type semiconductor material? a. fused b. interface c. alloyed d. point contact 53. When the reverse voltage increases, the capacitance a. decreases b. stays the same c. increases d. has more bandwidth 54. When the rms output voltage of a bridge full wave rectifier is 20 V, the peak inverse voltage across the diodes is (neglecting the diode drop) a. 28.3 V b. 20 V c. 40 V d. 56.6 V 55. A very high resistance connected in parallel with smoothing capacitors in a high voltage DC system is called a ___. a. dropping resistor b. shunt c. divider d. bleeder 56. The varactor is usually a. forward biased b. reverse biased c. unbiased d. operated in the breakdown region 57. Because the electrons enter the metal at an elevated energy level, schottky diodes are sometimes called a. snap-carrier diodes b. hot carrier diodes c. charge carrier diodes d. storage carrier diode 58. ____ refers to the measure of a power supply filter effectively. a. surge current b. average voltage value c. peak voltage value d. ripple factor 59. If line frequency is 60 Hz, the output frequency of a bridge rectifier is a. 30 Hz b. 60 Hz c. 120 Hz d. 240 Hz 60. The ideal dc output voltage of a capacitor input filter is equal to a. the average value of the rectified voltage b. the rms value of the rectified voltage c. the peak value of the rectified voltage d. either B or C 61. Which are the advantages of using an LED? a. Low power consumption and long life b. high lumens per cm and low voltage requirements c. a current flows when the device is exposed to a light source d. high lumens per cm and power consumption 62. Another name for zener voltage is a. forward breakdown voltage b. fixed breakdown voltage c. reverse breakdown voltage d. remote buffer voltage 63. A certain power supply filter produces an output with a ripple of 100 mV peak to peak and a dc value of 20 V. The ripple factor is a. 0.005 b. 0.05 c. 0.02 d. 0.00005 64. Refers to one of the main component of the alternating current power supply which converts the high voltage ac to fluctuating voltage direct current voltage a. voltage regulator b. rectifier c. filter d. power transformer 65. A/an ____ is a device that houses a light emitter and a light sensor in the same package. a. optocoupler b. oscillator c. Optoisolator d. A or C 66. With the same secondary voltage and filter, which has the most ripples? a. half wave rectifier b. full wave rectifier c. bridge rectifier d. impossible to say 67. A semiconductor ___ is simply a PN junction, but its applications are quite extensive. a. IC b. BJT c. FET d. diode 68. When the light increases, the reverse minority carrier current in a photodiode a. decreases b. increase c. is unaffected d. diode 69. How many diodes will you use in designing a half wave rectifier power supply? a. One b. two c. four d. three 70. What safety precautions should be observed when replacing a fuse? a. locate the fault that caused the blown fuse b. use the same exact voltage and current fuse c. turn off the power before replacing a fuse d. all of these 71. The device associated with voltage controlled capacitance is a a. light emitting diode b. photodiode c. varactor diode d. zener diode 72. To protect a load from excessive power supply voltages or currents, you could install: I. a zener diode II. A photodiode III. A crowbar circuit IV. A fuse or circuit breaker a. I and IV b. I,II and IV c. II, III and IV d. I, III and IV 73. A 60 V peak full wave rectified voltage is applied to a capacitor input filter. If f = 120 Hz, RL = 10 k and C = 10 F, the ripple voltage is a. 0.6 V b. 5.0 V c. 6 mV d. 2.88 V
74. If the depletion layer gets wider, the capacitance a. decreases b. stays the same c. increases d. is variable 75. A positive clamper clamps which extremity of the output signal to zero (0) volt? a. most positive b. half positive c. half negative d. most negative 76. With the same secondary voltage and filter, which produces the least load voltage? a. half wave rectifier b. full wave rectifier c. bridge rectifier d. impossible to say 77. If the load resistance of a capacitor filtered full wave rectifier is reduced, the ripple voltage a. is not affected b. increases c. decrease d. has a different frequency 78. Find the common use of a hot carrier diode a. as balance mixers in SSB generator b. as a constant voltage reference in a power supply c. as a variable capacitance in an automatic frequency control circuit d. as a VHF and UHF mixers and detectors 79. If the filtered load current is 10 mA, which of the following has a diode current of 10 mA? a. half wave rectifier b. full wave rectifier c. bridge rectifier d. impossible to say 80. How does zener diode widely used? a. voltage regulation b. power collectors c. variable resistor d. currents limiter 81. Line regulation is determined by a. zener current and load current b. changes in load resistance and output voltage c. load current d. changes in output and input voltage 82. Which of the following is photocell most sensitive to? a. heat b. light waves c. sound waves d. radio waves 83. If the load current is 5 mA and the filter capacitance is 1000F, what is the peak to peak ripple out of a bridge rectifier? a. 21.3 pV b. 56.3 mV c. 21.3 mV d. 41.7 mV 84. How is current through a LED limited to a safe value? a. a small value series resistor b. a large value resistor c. a parallel diode d. a capacitor to ground 85. Load regulations is determined by a. changes in zener current and load current b. changes in load current and output voltage c. changes in load current and input voltage d. changes in load resistance and input voltage 86. What do you call the resistor that is made of semiconductors designed to be extremely sensitive to temperature? a. potentiometer b. thermocouple c. thermistor d. varistor 87. The diodes in a bridge rectifier each have a maximum dc current rating of 2 A. this means the dc load current can have a maximum value of a. 1 A b. 2 A c. 4 A d. 6 A 88. How many half wave rectifiers will make up a half wave voltage doublers? a. 6 b. 2 c. 8 d. 4 89. A 10 V peak to peak sinusoidal voltage is applied across a silicon diode and series resistor. The maximum voltage across the diode is a. 0.7 V b. 10V c. 9.3 V d. 5 V 90. What kind of rectifier is used in an ac power supply which uses four diodes to attain full wave rectification of an ac input voltage without the need for a center tapped transformer? a. vacuum tube rectifier b. gas tube rectifier c. bridge rectifier d. selenium disk rectifier 91. What is the PIV across each diode of a bridge rectifier with a secondary voltage of 20 V rms? a. 14.1 V b. 20 V c. 28.3 Vd. 34 V 92. What is another name for a varactor diode? a. zener diode b. fast recovery diode c. voltage controlled capacitor d. four layer diode 93. If the input voltage to a voltage tripler has an rms value of 12 V, the dc output voltage is approximately a. 36 V b. 33.9 V c. 32.4V d. 50.9 V 94. What is the most important specification for semiconductor diode? a. forward resistance b. reverse resistance c. peak inverse voltage d. current capacity 95. A DMM uses the diode test function to check a diode. The DMM indicates .004 when the diode is tested in both directions. The diode is most likely a. open b. silicon type and is not defective c. shorted d. germanium type and is not defective 96. In half wave rectifier, if a resistance equal to load resistance is connected in parallel with the diode then a. circuit will stop rectifying b. output voltage would be halved c. output voltage would be doubled d. output voltage will remain unchanged 97. If the secondary voltage increases in a bridge rectifier with a capacitor input filter, the load voltage will a. decrease b. stay the same c. increase d. none of these 98. What is the purpose of the rectifier in a magnetic amplifier? a. centroid load current b. eliminates hysteresis loss c. controls gain d. control power loss 99. If one of the diode in a bridge full ways rectifier opens, the output is a
a. one fourth the amplitude of the input voltage b. 0 V c. 120 Hz voltage d. a half wave rectified voltage 100. Which of the following statement is true in semiconductor application? a. an ohmmeter test across a diode shows high resistance in both polarity at test b. an ohmmeter test across a diode shows low resistance in one polarity and high resistance in the opposite polarity c. an ohmmeter test across the base collector of a transistor should show low resistance for both polarities d. Triac is one direction semiconductor Prepared by: Engr. Denver G. Magtibay