INDIABIX-Part 1-ELEX-MCQs.pdf

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SEMICONDUCTORS

1. A silicon diode measures a low value 1. A silicon diode measures a low value of resistance with the meter leads in of resistance with the meter leads in both positions. The trouble, if any, is both positions. The trouble, if any, is A.

A. the the diode diode is is open.open. B.

B. the the diode diode is is shorted shorted to to ground.ground. C.

C. the the diode diode is is internally internally shorted.shorted. D.

D. the the diode diode is is working working correctly.correctly. 2. Single-element semiconductors are 2. Single-element semiconductors are characterized by atoms with ____ characterized by atoms with ____ valence electrons. valence electrons. A. 3 A. 3 B. B. 44 C. 5 C. 5 D. 2 D. 2

3. Under normal conditions a diode 3. Under normal conditions a diode conducts current when it is

conducts current when it is A. reverse-biased. A. reverse-biased. B. forward-biased. B. forward-biased. C. avalanched. C. avalanched. D. saturated. D. saturated.

4. A diode conducts when it is 4. A diode conducts when it is forward-biased, and the anode is connected to biased, and the anode is connected to the ________ through a limiting resistor. the ________ through a limiting resistor. A.

A. positive positive supplysupply B.

B. negative negative supplysupply C. cathode

C. cathode

D. anode

5. As the forward current through a 5. As the forward current through a silicon diode increases, the internal silicon diode increases, the internal resistance resistance A. increases. A. increases. B. decreases. B. decreases. C.

C. remains remains the the same.same.

6. The movement of free electrons in a 6. The movement of free electrons in a conductor is called conductor is called A. voltage. A. voltage. B. current. B. current. C. recombination. C. recombination. D. equilibrium. D. equilibrium.

7. For a forward-biased diode, the

7. For a forward-biased diode, the barrierbarrier potential ________ as temperature potential ________ as temperature increases. increases. A. decreases A. decreases B.

B. remains remains constantconstant C. increases

C. increases

8. The wide end arrow on a schematic 8. The wide end arrow on a schematic indicates the ________ of a diode.

indicates the ________ of a diode. A. ground

A. ground B.

B. direction direction of of electron electron flowflow C. cathode

C. cathode

D. anode

9. An n-type semiconductor material 9. An n-type semiconductor material A.

A. is is intrinsic.intrinsic. B.

B. has has trivalent trivalent impurity impurity atomsatoms added.

added. C.

C. has has pentavalent pentavalent impurityimpurity atoms added.

atoms added. D.

D. requires requires no no doping.doping.

10. For a forward-biased diode, as 10. For a forward-biased diode, as temperature is ________, the forward temperature is ________, the forward current ________ for a given value of current ________ for a given value of forward voltage.

forward voltage. A.

A. decreased, decreased, increasesincreases B.

B. increased, increased, increasesincreases C.

C. increased, increased, decreasesdecreases D.

D. decreased, decreased, decreasesdecreases 11.

11. Which Which statement statement best best describesdescribes an insulator?

an insulator? A.

A. A A material material with with many many freefree electrons.

electrons. B.

B. A A material material doped doped to to have have somesome free electrons.

free electrons. C.

C. A A material material with with few few freefree electrons.

electrons. D.

D. No No description description fits.fits.

12. Effectively, how many valence 12. Effectively, how many valence electrons are there in each atom within a electrons are there in each atom within a silicon crystal? silicon crystal? A. 2 A. 2 B. 4 B. 4 C. 8 C. 8 D. 16 D. 16

13. The boundary between p-type 13. The boundary between p-type material and n-type material is called material and n-type material is called A.

A. a a diode.diode. B.

B. a a reverse-biased reverse-biased diode.diode. C.

C. a a pn pn junction.junction. D.

D. a a forward-biased forward-biased diode.diode.

14. You have an unknown type of diode 14. You have an unknown type of diode in a circuit. You measure the voltage in a circuit. You measure the voltage across it and find it to be 0.3 V. The across it and find it to be 0.3 V. The diode might be

diode might be A.

A. a a silicon silicon diode.diode. B.

B. a a germanium germanium diode.diode. C.

C. a a forward-biased forward-biased silicon silicon diode.diode. D.

D. a a reverse-biased reverse-biased germaniumgermanium diode.

diode.

15. An ideal diode presents a(n) 15. An ideal diode presents a(n) ________ when reversed-biased and a(n) ________ when reversed-biased and a(n) ________ when forward-biased.

________ when forward-biased. A.

A. open, open, shortshort B.

B. short, short, openopen C.

C. open, open, openopen D.

D. short, short, shortshort

16. A reverse-biased diode has the 16. A reverse-biased diode has the ________ connected to the positive side ________ connected to the positive side of the source, and the ________ of the source, and the ________ connected to the negative side of the connected to the negative side of the source.

source. A.

A. cathode, cathode, anodeanode B.

B. cathode, cathode, basebase C.

C. base, base, anodeanode D.

D. anode, anode, cathodecathode

17. What types of impurity atoms are 17. What types of impurity atoms are added to increase the number of added to increase the number of conduction-band electrons in intrinsic conduction-band electrons in intrinsic silicon? silicon? A. bivalent A. bivalent B. octavalent B. octavalent C. pentavalent C. pentavalent D. trivalent D. trivalent E.

E. none none of of the the aboveabove

18. What factor(s) do(es) the barrier 18. What factor(s) do(es) the barrier potential of a pn junction depend on? potential of a pn junction depend on? A.

A. type type of of semiconductivesemiconductive material

material B.

B. the the amount amount of of dopingdoping C.

C. the the temperaturetemperature D.

D. all all of of the the aboveabove E.

E. type type of of semiconductivesemiconductive material and the amount of material and the amount of doping but not the temperature doping but not the temperature 19. An atom is made up of 19. An atom is made up of A. protons. A. protons. B. neutrons. B. neutrons. C. electrons. C. electrons. D.

D. all all of of the the aboveabove

20. Reverse breakdown is a condition in 20. Reverse breakdown is a condition in which a diode

which a diode A.

A. is is subjected subjected to to a a large large reversereverse voltage.

voltage. B.

B. is is reverse-biased reverse-biased and and there there is is aa small

small leakage leakage current.current. C.

C. has has no no current current flowing flowing at at all.all. D.

D. is is heated heated up up by by large large amountsamounts of cur

of current in rent in the the forward forward direction.direction. 21. There is a small amount of current 21. There is a small amount of current across the barrier of a reverse-biased across the barrier of a reverse-biased diode. This current is called

diode. This current is called A.

A. forward-bias forward-bias current.current. B.

B. reverse reverse breakdown breakdown current.current. C.

C. conventional conventional current.current. D.

D. reverse reverse leakage leakage current.current.

22. As the forward current through a 22. As the forward current through a silicon diode increases, the voltage silicon diode increases, the voltage across the diode

across the diode A.

A. increases increases to to a a 0.7 0.7 V V maximum.maximum. B. decreases.

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C.

C. is is relatively relatively constant.constant. D.

D. decreases decreases and and then then increases.increases. 23. Doping of a semiconductor material 23. Doping of a semiconductor material means

means A.

A. that that a a glue-type glue-type substance substance isis added to hold the added to hold the material together.

material together. B.

B. that that impurities impurities are are added added toto increase

increase the the resistance resistance ofof the material.

the material. C.

C. that that impurities impurities are are added added toto decrease

decrease the the resistance resistance ofof the material.

the material. D.

D. that that all all impurities impurities are are removedremoved to get pure silicon.

to get pure silicon.

24. The forward voltage across a 24. The forward voltage across a conducting silicon diode is about

conducting silicon diode is about A. A. 0.3 0.3 V.V. B. B. 1.7 1.7 V.V. C. C. ––0.7 V.0.7 V. D. D. 0.7 0.7 V.V.

25. The most common type of diode 25. The most common type of diode failure is a(n) ________. failure is a(n) ________. A. open A. open B. short B. short C. resistive C. resistive

26. What occurs when a 26. What occurs when a conduction-band electron loses energy and falls band electron loses energy and falls back into a hole in the valence band? back into a hole in the valence band? A. doping A. doping B. recombination B. recombination C. generation C. generation 27

27.. The maximum number of electrons in The maximum number of electrons in

each shell of an atom is each shell of an atom is

A. 2.

B. 2n

B. 2n22 where n is the number of where n is the number of the shell. the shell. C. 4. C. 4. D. 8. D. 8.

28. A silicon diode is forward-biased. 28. A silicon diode is forward-biased. You measure the voltage to ground from You measure the voltage to ground from the anode at ________, and the voltage the anode at ________, and the voltage from the cathode to ground at from the cathode to ground at ________. ________. A. A. 0 0 V, V, 0.3 0.3 VV B. B. 2.3 2.3 V, V, 1.6 1.6 VV C. C. 1.6 1.6 V, V, 2.3 2.3 VV D. D. 0.3 0.3 V, V, 0 0 VV

29. The term bias in electronics usually 29. The term bias in electronics usually means

means A.

A. the the value value of of ac ac voltage voltage in in thethe signal.

signal. B.

B. the the condition condition of of currentcurrent through a pn junction.

through a pn junction.

C.

C. the the value value of of dc dc voltages voltages forfor the device to operate the device to operate properly.

properly. D.

D. the the status status of of the the diode.diode.

SPECIAL- PURPOSE

DIODES

1. Schottky diodes are also known as 1. Schottky diodes are also known as A.

A. PIN PIN diodes.diodes. B.

B. hot hot carrier carrier diodes.diodes. C.

C. step-recovery step-recovery diodes.diodes. D.

D. tunnel tunnel diodes.diodes.

2. Zener diodes with breakdown 2. Zener diodes with breakdown voltages less than 5 V operate voltages less than 5 V operate predominantly in what type of predominantly in what type of breakdown? breakdown? A. avalanche A. avalanche B. zener B. zener C. varactor C. varactor D. Schottky D. Schottky

3. The Schottky diode is used 3. The Schottky diode is used A.

A. in in high-power high-power circuits.circuits. B.

B. in in circuits circuits requiring requiring negativenegative resistance.

resistance. C.

C. in in very very fast-switching fast-switching circuitcircuit D.

D. in in power power supply supply rectifiersrectifiers

4. You have an application for a diode to 4. You have an application for a diode to be used in a tuning circuit. A type of be used in a tuning circuit. A type of diode to use might be

diode to use might be A.

A. an an LED.LED. B.

B. a a Schottky Schottky diode.diode. C.

C. a a Gunn Gunn diode.diode. D.

D. a a varactor.varactor.

5. Refer to this figure. Which symbol is 5. Refer to this figure. Which symbol is correct for an LED?

correct for an LED?

A. a A. a B. b B. b C. c C. c D. d D. d E. e E. e

6. Refer to this figure. If V

6. Refer to this figure. If VININ increases, I increases, IZZ will will A. increase. A. increase. B. decrease. B. decrease. C.

C. remain remain the the same.same.

7. What kind of diode is formed by 7. What kind of diode is formed by joining

joining a a doped doped semiconductor semiconductor regionregion with a metal? with a metal? A. laser A. laser B. tunnel B. tunnel C. pin C. pin D. Schottky D. Schottky

8. Refer to this figure. Which symbol is 8. Refer to this figure. Which symbol is correct for a zener diode?

correct for a zener diode?

9. Which diode employs graded doping? 9. Which diode employs graded doping? A. zener A. zener B. LED B. LED C. tunnel C. tunnel D. step-recovery D. step-recovery

10. Refer to this figure. Identify the 10. Refer to this figure. Identify the Schottky diode. Schottky diode. A. a A. a B. b B. b C. c C. c D. d D. d E. e E. e

11. LEDs are made out of 11. LEDs are made out of A. silicon. A. silicon. B. germanium. B. germanium. C. gallium. C. gallium. D.

D. silicon silicon and and germanium, germanium, but but notnot gallium.

gallium.

12. The normal operating region for a 12. The normal operating region for a zener diode is the

zener diode is the A.

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B.

B. reverse-bias reverse-bias region.region. C.

C. zero-crossing zero-crossing region.region. D.

D. reverse-breakdown reverse-breakdown region.region. 13. Refer to this figure. If V

13. Refer to this figure. If VININ attempts to attempts to increase, V

increase, VRR will will

A. increase. A. increase. B. decrease. B. decrease. C.

14. An LED is forward-biased. The diode 14. An LED is forward-biased. The diode should be on, but no light is showing. A should be on, but no light is showing. A possible trouble might be

possible trouble might be A.

A. the the diode diode is is open.open. B.

B. the the series series resistor resistor is is too too small.small. C.

C. none. none. The The diode diode should should be be off off ifif forward-biased.

forward-biased. D.

D. the the power power supply supply voltage voltage is is tootoo high.

high.

15. A 6.2 V zener is rated at 1 watt. The 15. A 6.2 V zener is rated at 1 watt. The maximum safe current the zener can maximum safe current the zener can carry is carry is A. A. 1.61 1.61 A.A. B. B. 161 161 mA.mA. C. C. 16.1 16.1 mA.mA. D. D. 1.61 1.61 mA.mA.

16. Refer to this figure. Find the tunnel 16. Refer to this figure. Find the tunnel diode symbol. diode symbol. A. a A. a B. b B. b C. c C. c D. d D. d E. e E. e

17. Refer to this figure. If the l

17. Refer to this figure. If the load currentoad current increases, I

increases, IRR will _____ and I will _____ and IZZ will _____. will _____.

A.

A. remain remain the the same, same, increaseincrease B.

B. decrease, decrease, remain remain the the samesame C.

C. increase, increase, remain remain the the samesame D.

D. remain remain the the same, same, decreasedecrease

18. The process of emitting photons 18. The process of emitting photons from a semiconductive material is called from a semiconductive material is called A. photoluminescence.

A. photoluminescence. B.

B. gallium gallium arsenide.arsenide. C. electroluminescence. C. electroluminescence. D.

D. gallium gallium phosphide.phosphide.

19. An 8.2 V zener has a resistance of 19. An 8.2 V zener has a resistance of 5Ω. The actual voltage across its 5Ω. The actual voltage across its terminals when the current is 25 mA is terminals when the current is 25 mA is A. A. 8.2 8.2 V.V. B. B. 125 125 mV.mV. C. C. 8.325 8.325 V.V. D. D. 8.075 8.075 V.V.

20. What diode operates only with 20. What diode operates only with majority carriers? majority carriers? A. laser A. laser B. tunnel B. tunnel C. Schottky C. Schottky D. step-recovery D. step-recovery

21. Refer to this figure. Which symbol is 21. Refer to this figure. Which symbol is correct for a photodiode?

correct for a photodiode?

22. What type of diode maintains a 22. What type of diode maintains a constant current? constant current? A. LED A. LED B. zener B. zener C.

C. current current regulatorregulator

D. pin

E.

E. none none of of the the aboveabove 23. What diode is used in

23. What diode is used in seven-segmentseven-segment displays? displays? A. zener A. zener B. LED B. LED C. laser C. laser D. Schottky D. Schottky

24. Refer to this figure. If V

24. Refer to this figure. If VININ decreases, decreases, IIRR will will A. increase. A. increase. B. decrease. B. decrease. C.

25. Zener diodes with breakdown 25. Zener diodes with breakdown voltages greater than 5 V operate voltages greater than 5 V operate predominantly in what type of predominantly in what type of breakdown? breakdown? A. avalanche A. avalanche B. zener B. zener C. varactor C. varactor D. Schottky D. Schottky

26. Back-to-back varactor diodes are 26. Back-to-back varactor diodes are used for what reason?

used for what reason? A.

A. over-voltage over-voltage protectionprotection B.

B. a a wider wider tuning tuning rangerange C.

C. to to eliminate eliminate harmonicharmonic distortion

distortion D.

D. no no reason; reason; only only zeners zeners are are usedused

in a back-to-back

configuration configuration 27. A tunnel diode is used 27. A tunnel diode is used A.

A. in in high-power high-power circuits.circuits. B.

B. in in circuits circuits requiring requiring negativenegative resistance.

resistance. C.

C. in in very very fast-switching fast-switching circuits.circuits. D.

D. in in power power supply supply rectifiers.rectifiers. 28. What type of diode is commonly 28. What type of diode is commonly used in electronic tuners in TVs?

used in electronic tuners in TVs? A. varactor A. varactor B. Schottky B. Schottky C. LED C. LED D. Gunn D. Gunn

29. A laser diode normally emits 29. A laser diode normally emits A.

A. coherent coherent light.light. B.

B. monochromatic monochromatic light.light. C.

C. coherent coherent and and monochromaticmonochromatic light.

light.

D. neither coherent nor D. neither coherent nor

monochromatic light. monochromatic light.

30. A varactor is a pn junction diode that 30. A varactor is a pn junction diode that always operates in ________-bias and is always operates in ________-bias and is doped to ________ the inherent doped to ________ the inherent capacitance of the depletion region. capacitance of the depletion region. A.

A. forward, forward, maximizemaximize B.

B. reverse, reverse, maximizemaximize C.

C. reverse, reverse, minimizeminimize D.

D. forward, forward, minimizeminimize

BIPOLAR JUNCTION

TRANSISTORS

1. Refer to this figure. Determine the 1. Refer to this figure. Determine the minimum value of I

minimum value of IBB that will produce that will produce saturation.

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A. 0.25 mA B. 5.325 µA C. 1.065 µA D. 10.425 µA

2. A transistor amplifier has a voltage gain of 100. If the input voltage is 75 mV, the output voltage is:

A. 1.33 V B. 7.5 V C. 13.3 V D. 15 V

3. Refer to this figure. If VCE = 0.2 V, IC(sat) is:

A. 0.05 mA B. 2.085 mA C. 1.065 mA D. 7.4 mA

4. What is the ratio of IC to IB?

A. βDC

B. hFE

C. αDC

D. either βDC or h_FE, but not αDC

5. For normal operation of a pnp BJT, the base must be ________ with respect to the emitter and ________ with respect to the collector.

A. positive, negative B. positive, positive C. negative, positive D. negative, negative

6. Refer to this figure. The value of VBCis:

A. 9.2 V B. 9.9 V

C. –9.9 V

D. –9.2 V

7. When a transistor is used as a switch, it is stable in which two distinct regions? A. saturation and active

B. active and cutoff C. saturation and cutoff D. none of the above 8. The term BJT is short for A. base junction transistor. B. binary junction transistor. C. both junction transistor. D. bipolar junction transistor 9. For a silicon transistor, when a base-emitter junction is forward-biased, it has a nominal voltage drop of

A. 0.7 V. B. 0.3 V. C. 0.2 V. D. VCC.

10. A certain transistor has IC = 15 mA and IB = 167µ

A;

βDC is:

A. 15

B. 167

C. 0.011

D. 90

11. Refer to this figure. The value of VCE is:

A. 9.9 V B. 9.2 V C. 0.7 V D. 19.3 V

12. What does βDCvary with?

A. IC

B. ºC

C. both IC and ºC D. IC, but not ºC

13. A BJT has an IB of 50µA and a βDCof

75; IC is:

A. 375 mA B. 37.5 mA C. 3.75 mA D. 0.375 mA

14. Refer to this figure. The value of VBE is:

A. 0.6 V B. 0.7 V C. 1.2 V D. 0.079 V

15. What are the two types of bipolar junction transistors?

A. npn and pnp B. pnn and nnp C. ppn and nnp D. pts and stp

16. In this circuit βDC= 100 and V_IN = 8 V.

The value of RB that will produce saturation is: A. 92 kΩ B. 9.1 MΩ C. 100 kΩ D. 150 kΩ 17. The value of βDC

A. is fixed for any particular transistor.

B. varies with temperature. C. varies with IC.

D. varies with temperature and IC.

18. A transistor data sheet usually identifiesβDC as

A. hre. B. hFE. C. IC. D. VCE.

19. What is the ratio of IC to IE?

A. βDC

B. βDC / (βDC + 1)

C. βDC

D. either βDC/ (βDC + 1) or αDC, but

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20. Refer to this figure. The value of βDC = 100 and VIN = 8 V. Determine IC(sat).

A. 18 mA

B. 7.92 mA C. 1.8 mA D. 8 µA

21. Which of the following is true for an npn or pnp transistor?

A. IE = IB + IC B. IB = IC+ IE C. IC = IB + IE

D. none of the above

22. What is the order of doping, from heavily to lightly doped, for each region? A. base, collector, emitter

B. emitter, collector, base C. emitter, base, collector D. collector, emitter, base 23. In what range of voltages is the transistor in the linear region of its operation?

A. 0 < VCE

B. 0.7 < VCE < VCE(max) C. VCE(max)> VCE D. none of the above

24. The magnitude of dark current in a phototransistor usually falls in what range?

A. mA

B. μA

C. nA

D. pA

25. A 35 mV signal is applied to the base of a properly biased transistor with an r'e = 8 and RC = 1 k. The output signal voltage at the collector is:

A. 3.5 V B. 28.57 V C. 4.375 mV D. 4.375 V

26. What is (are) general-purpose/small-signal transistors case type(s)?

A. TO-18

B. TO-92

C. TO-39

D. TO-52

E. all of the above

27. What is (are) common fault(s) in a BJT-based circuit?

A. opens or shorts internal to the transistor

B. open bias resistor(s)

C. external opens and shorts on the circuit board

D. all of the above

28. The dc load line on a family of collector characteristic curves of a transistor shows the

A. saturation region. B. cutoff region. C. active region. D. all of the above

29. Refer to this figure. Determine the minimum value of VINfrom the following that will saturate this transistor.

A. 13.21 V B. 12.51 V C. 0.7 V D. 9.4 V

BJT DEVICES

1. How much is the base-to-emitter voltage of a transistor in the "on" state?

A. 0 V

B. 0.7 V C. 0.7 mV D. Undefined

2. How many layers of material does a transistor have?

A. 1

B. 2

C. 3

D. 4

3. Which of the following equipment can check the condition of a transistor? A. Current tracer

B. Digital display meter (DDM) C. Ohmmeter (VOM)

D. All of the above

4. For what kind of amplifications can the active region of the common-emitter configuration be used?

A. Voltage B. Current

C. Power

D. All of the above

5. In the active region, while the collector-base junction is biased, the base-emitter is ________-biased.

A. forward, forward B. forward, reverse C. reverse, forward D. reverse, reverse

6. A transistor can be checked using a(n) ________.

A. curve tracer B. digital meter C. ohmmeter

D. Any of the above

7. What range of resistor values would you get when checking a transistor for forward- and reverse-biased conditions by an ohmmeter? A. 100 to a few kΩ, exceeding 100 kΩ B. Exceeding 100 kΩ, 100 to a few kΩ C. Exceeding 100 kΩ, exceeding 100 kΩ D. 100Ω to a few kΩ, 100Ω to a few kΩ

8. Calculate minority current ICO if IC = 20.002 mA and IC majority = 20 mA.

A. 20 µA

B. 0.002 µA C. 2 nA D. 2 µA

9. What is (are) the component(s) of electrical characteristics on the specification sheets?

A. On

B. Off

C. Small-signal characteristics D. All of the above

10. In which region are both the collector-base and base-emitter junctions forward-biased?

A. Active B. Cutoff C. Saturation D. All of the above

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11. An example of a pnp silicon transistor is a 2N4123.

A. True B. False

12. Which of the following is (are) the terminal(s) of a transistor?

A. Emitter

B. Base

C. Collector

D. All of the above

13. Use this table of collector characteristics to calculate βac at V_CE = 15

V and IB= 30 µA.

A. 100

B. 106

C. 50

D. 400

14. Which of the following configurations can a transistor set up? A. Common-base

B. Common-emitter C. Common-collector D. All of the above

15. What does a reading of a large or small resistance in forward- and reverse-biased conditions indicate when checking a transistor using an ohmmeter?

A. Faulty device B. Good device C. Bad ohmmeter D. None of the above

16. Determine the value of α when β = 100.

A. 1.01

B. 101

C. 0.99

D. Cannot be solved with the information provided

17. Transistors are ________-terminal devices. A. 2 B. 3 C. 4 D. 5 18. Calculate βdc at V_CE = 15 V and I_B = 30 µA. A. 100 B. 116 C. 50 D. 110

19. Which of the following can be obtained from the last scale factor of a curve tracer?

A. hFE

B. αdc

C. αac

D. βac

20. Calculate βac for I_C = 15 mA and V_CE =

5 V.

A. 200

B. 180

C. 220

D. None of the above 21. βdc= ________

A. IB / IE B. IC / IE C. IC / IB

D. None of the above

22. How many carriers participate in the injection process of a unipolar device?

A. 1

B. 2

C. 0

D. 3

23. What are the ranges of the ac input and output resistance for a common-base configuration?

A. 10Ω–100Ω , 50 kΩ –1 MΩ B. 50 kΩ –1 MΩ, 10 Ω – 100Ω C. 10 Ω–100 kΩ, 50 Ω –1 kΩ D. None of the above

24. What is the most frequently encountered transistor configuration?

A. Common-base B. Common-collector C. Common-emitter D. Emitter-collector 25.βdcfor this set of collector

characteristics is within ________ percent of

β

ac. A. 2 B. 5 C. 7 D. 10

26. Which of the following regions is (are) part of the output characteristics of a transistor?

A. Active B. Cutoff C. Saturation D. All of the above

27. How many individual pnp silicon transistors can be housed in a 14-pin plastic dual-in-line package?

A. 4

B. 7

C. 10

D. 14

28. In what decade was the first transistor created?

A. 1930s

B. 1940s

C. 1950s D. 1960s

29. Most specification sheets are broken down into ________.

A. maximum ratings B. thermal characteristics C. electrical characteristics D. All of the above

30. For a properly biased pnp transistor, let IC = 10 mA and IE = 10.2 mA. What is the level of IB?

A. 0.2 A B. 200 mA C. 200 µA D. 20.2 ma

31. What is (are) the component(s) of most specification sheets provided by the manufacturer?

(8)

A. Maximum ratings B. Thermal characteristics C. Electrical characteristics D. All of the above

32. What is βdc equal to? A. IB / IE

B. IC / IE C. IC / IB

33. List the types of bipolar junction transistors.

A. ppn, npn B. pnp, npn C. npp, ppn D. nnp, pnp

34. What is the ratio of the total width to that of the center layer for a transistor? A. 1:15

B. 1:150 C. 15:1 D. 150:1

35. Which component of the collector current IC is called the leakage current? A. Majority

B. Independent C. Minority

BJT AMPLIFIERS

1. The current gain for the Darlington connection is ________.

A. β1

· (

β2

/2)

B. β1

·

β2 C. β1

/

β2 D. β1

· (

β2

-1)

2. Which of the following configurations has the lowest output impedance? A. Fixed-bias

B. Voltage-divider C. Emitter-follower D. None of the above

3. Which of the h-parameters corresponds to re in a common-base configuration? A. hib B. hfb C. hrb D. hob

4. Refer to this figure. Find the value of IE.

A. 2 mA

B. 4 mA

C. 5 mA

D. 6 mA

5. Which of the following is referred to as the reverse transfer voltage ratio?

A. hi

B. hr C. hf D. ho

6. Which of the following conditions must be met to allow the use of the approximate approach in a voltage-divider bias configuration?

A. βre > 10R2 B. βre > 10R2 C. βre < 10R2 D. βre < 10R2

7. Refer to this figure. Determine the value of Av.

A. 49.6

B. 5

C. 100

D. 595

8. For a common-emitter amplifier, the purpose of swamping is

A. to minimize gain.

B. to reduce the effects of r'e C. to maximize gain.

D. no purpose.

9. What is the typical value of the current gain of a common-base configuration?

A. Less than 1 B. Between 1 and 50 C. Between 100 and 200 D. Undefined

10. What is the most important r parameter for amplifier analysis?

A. rb′ B. rc′ C. re′

11. An emitter-follower is also known as: A. common-emitter amplifier. B. common-base amplifier. C. common-collector amplifier. D. Darlington pair.

12. The ________ model fails to account for the output impedance level of the device and the feedback effect from output to input.

A. hybrid equivalent B. re

C. β

D. Thevenin

13. Refer to this figure. Calculate the value of VB.

A. 5 V

B. 3.7 V C. 20 V

D. 3 V

14. You have a need to apply an amplifier with a very high power gain. Which of the following would you choose?

A. common-collector B. common-base C. common-emitter D. emitter-follower

15. What is the voltage gain of a feedback pair connection?

A. 1

B. –1

C. 100

D. –100

16. A common-emitter amplifier has ________ voltage gain, ________ current gain, ________ power gain, and ________ input impedance.

(9)

B. high, high, high, low C. high, high, high, high D. low, low, low, high

17. What is the range of the input impedance of a common-base configuration?

A. A few ohms to a maximum of 50 Ω

B. 1 kΩ to 5 kΩ C. 100 kΩ to 500 kΩ D. 1 MΩ to 2 MΩ

18. The advantage that a Sziklai pair has over a Darlington pair is

A. higher current gain.

B. less input voltage is needed to turn it on.

C. higher input impedance. D. higher voltage gain.

19. What is the typical range of the output impedance of a common-emitter configuration?

A. 10Ω to 100Ω B. 1 kΩ to 5 kΩ C. 40 kΩ to 50 kΩ D. 500 kΩ to 1 kΩ

20. What is the unit of the parameter ho? A. Volt

B. Ohm

C. Siemen D. No unit

21. Refer to this figure. Calculate the value of Rin(tot).

A. 37.7 kΩ B. 3.77 kΩ C. 378 Ω D. 2.25 kΩ

22. What is the range of the current gain for BJT transistor amplifiers?

A. less than 1 B. 1 to 100 C. above 100 D. All of the above

23. What does the negative sign in the voltage gain of the common-emitter fixed-bias configuration indicate?

A. The output and input voltages are 180º out of phase.

B. Gain is smaller than 1. C. Gain is larger than 1. D. None of the above

24. For the common-emitter fixed-bias configuration, there is a ________ phase shift between the input and output signals.

A. 0º

B. 45º

C. 90º

D. 180º

25. Which one of the following configurations has the lowest input impedance?

A. Fixed-bias B. Common-base C. Emitter-follower D. Voltage-divider?

26. Which of the following represent(s) the advantage(s) of the system approach over the r-model approach? A. Thevenin's theorem can be

used.

B. The effect of changing the load can be determined by a simple equation.

C. There is no need to go back to

the ac equivalent

model and analyze the entire network.

D. All of the above

27. The differential amplifier has A. one input and one output. B. two inputs and two outputs. C. two inputs and one output. D. one input and two outputs. 28. The emitter-follower configuration has a ________ impedance at the input and a ________ impedance at the output.

A. low, low B. low, high C. high, low D. high, high

29. The differential amplifier produces outputs that are

A. common mode.

B. in-phase with the input voltages.

C. the sum of the two input voltages.

D. the difference of the two input voltages.

30. The ________ model suffers from being limited to a particular set of operating conditions if it is to be considered accurate. A. hybrid equivalent B. re C. β D. Thevenin

31. Under which of the following condition(s) is the current gain Av≈ β ? A. ro 10RC

B. RB 10re

C. ro 10RC and RB 10re D. None of the above

32. The ________ configuration is frequently used for impedance matching.

A. fixed-bias

B. voltage-divider bias C. emitter-follower D. collector feedback

33. Refer to this figure. You notice while servicing this amplifier that the output signal at Vout is reduced from normal. The problem could be caused by

A. an open C3. B. an open C2.

C. an open base-emitter of Q2. D. a shorted C2.

34. When the bypass capacitor is removed from a common-emitter amplifier, the voltage gain

A. increases. B. decreases.

C. has very little effect.

35. Refer to this figure. Determine the value of VC.

(10)

A. 20 V B. 10 V

C. 5 V

D. 0 V

36. In a common-base amplifier, the input signal is connected to the

A. base. B. collector. C. emitter. D. output.

37. Which of the following is (are) true to achieve a good overall voltage gain for the circuit?

A. The effect of Rs and RL must be considered as a product. B. The effect of Rs and RL must

be considered as a product and evaluated individually.

C. The effect of Rs and RL must be evaluated individually.

38. To analyze the common-emitter amplifier, what must be done to determine the dc equivalent circuit? A. leave circuit unchanged

B. replace coupling and bypass capacitors with opens

C. replace coupling and bypass capacitors with shorts

D. replace VCC with ground

39. For the common-emitter amplifier ac equivalent circuit, all capacitors are A. effectively shorts.

B. effectively open circuits. C. not connected to ground. D. connected to ground.

40. Refer to this figure. If an emitter bypass capacitor was installed, determine the value of Rin(base).

A. 416 Ω

B. 5 kΩ

C. 50 kΩ

D. 500 Ω

41. Under which of the following conditions is the output impedance of the network approximately equal to RC for a common-emitter fixed-bias configuration?

A. ro 10RC B. ro < 10RC C. ro < ro D. ro > ro

42. Which of the following gains is less than 1 for a common-base configuration?

A. Ai

B. Av

C. Ap

43. Which of the following define(s) the conversion efficiency?

A. Ac power to the load/ac input power

B. Ac power to the load/dc power supplied

C. Dc output power/ac input power

D. All of the above

44. The dc emitter current of a transistor is 8 mA. What is the value of re?

A. 320 Ω

B. 13.3 kΩ C. 3.125 Ω D. 5.75 Ω

45. Which of the following should be done to obtain the ac equivalent of a network?

A. Set all dc sources to zero

B. Replace all capacitors by a short-circuit equivalent.

C. Remove all elements bypassed by the short-circuit equivalent.

D. All of the above

46. In an un-bypassed emitter bias configuration hie replaces ________ in the re model. A. re B. β C. βre D. Ib

47. Which of the following is (are) true regarding the input impedance for frequencies in the midrange 100 kHz of a BJT transistor amplifier?

A. The input impedance is purely resistive.

B. It varies from a few ohms to megohms.

C. An ohmmeter cannot be used to measure the small-signal ac input impedance. D. All of the above

48. For the collector dc feedback configuration, there is a ________ phase shift between the input and output signals.

A. 0º

B. 45º

C. 90º

D. 180º

49. A common-collector amplifier has ________ input resistance, ________ current gain, and ________ voltage gain. A. high, high, low

B. high, low, low C. high, low, high

50. The total gain of a multistage amplifier is the ________.

A. sum of individual voltage gains B. sum of dB voltage gains

51. Which of the following configurations has an output impedance Zo equal to RC?

A. Fixed-bias common-emitter B. Common-emitter

voltage-divider with bypass capacitor

C. Common-emitter voltage-divider without bypass capacitor

D. All of the above

52. Refer to this figure. Find the value of Rin(base).

(11)

A. 420

Ω

B. 50 kΩ

C. 940

Ω

D. 100.8

Ω

53. For a common-emitter amplifier, the purpose of the emitter bypass capacitor is

A. no purpose, since it is shorted out by RE.

B. to reduce noise.

C. to despike the supply voltage. D. to maximize amplifier gain. 54. For BJT amplifiers, the ________ gain typically ranges from a level just less than 1 to a level that may exceed 1000. A. voltage

B. current C. impedance D. All of the above

55. The loaded voltage gain of an amplifier is always more than the no-load level.

A. True B. False

56. Which of the following configurations has a voltage gain of –RC /re?

A. Fixed-bias common-emitter B. Common-emitter

voltage-divider with bypass capacitor

C. Fixed-bias common-emitter and voltage-divider with bypass capacitor

D. Common-emitter voltage-divider without bypass capacitor

57. An emitter-follower amplifier has an input impedance of 107 kΩ. The input signal is 12 mV. The approximate output voltage is (common-collector)

A. 8.92 V B. 112 mV

C. 12 mV

D. 8.9 mV

58. Which of the following is (are) true regarding the output impedance for frequencies in the midrange 100 kHz of a BJT transistor amplifier?

A. The output impedance is purely resistive.

B. It varies from a few ohms to more than 2 MΩ.

C. An ohmmeter cannot be used to measure the small-signal ac output impedance. D. All of the above

59. Refer to this figure. The output signal from the first stage of this amplifier is 0 V. The trouble could be caused by

A. an open C4. B. an open C2.

C. an open base-emitter of Q1. D. a shorted C4.

60. What is the limit of the efficiency defined by = Po / Pi?

A. Greater than 1 B. Less than 1 C. Always 1

61. What is re equal to in terms of h parameters?

A. hre / hoe B. (hre + 1) / hoe

C. hie– (hre/ hoe)(1 + hfe) D. hfe

E. none of the above

62. What is the controlling current in a common-base configuration?

A. Ie B. Ic C. Ib

63. Which of the following techniques can be used in the sinusoidal ac analysis of transistor networks?

A. Small-signal B. Large-signal

C. Small- or large-signal D. None of the above

64. The input impedance of a BJT amplifier is purely ________ in nature and can vary from a few ________ to ________.

A. resistive, ohms, megohms B. capacitive, microfarads, farads C. inductive, millihenrys, henrys D. None of the above

65. The ________ the source resistance and/or ________ the load resistance, the less the overall gain of an amplifier. A. smaller, smaller

B. smaller, larger C. larger, smaller D. larger, larger

66. Refer to this figure. If an emitter bypass capacitor was installed, what would the new Av be?

A. 4.96

B. 125

C. 398

D. 600

67. A Darlington pair provides beta ________ for ________ input resistance. A. multiplication, decreased B. multiplication, increased C. division, decreased

68. A Darlington pair amplifier has

A. high input impedance and high voltage gain.

B. low input impedance and low voltage gain.

C. a voltage gain of about 1 and a low input impedance.

D. a low voltage gain and a high input impedance.

FET DEVICES

1. Which of the following ratings appear(s) in the specification sheet for an FET?

A. Voltages between specific terminals

(12)

C. Power dissipation D. All of the above

2. What is the level of drain current ID for gate-to-source voltages VGS less than (more negative than) the pinch-off level?

A. zero amperes B. IDSS

C. Negative value D. Undefined

3. What is the level of IG in an FET? A. Zero amperes

B. Equal to ID C. Depends on VDS D. Undefined

4. What is the range of an FET's input impedance?

A. 10

Ω

to 1 k

Ω

B. 1 k

Ω

to 10 k

Ω

C. 50 k

Ω

to 100 k

Ω

D. 1 MΩ to several hundred MΩ 5. Which of the following applies to a safe MOSFET handling?

A. Always pick up the transistor by the casing.

B. Power should always be off when network changes are made. C. Always touch ground before

handling the device. D. All of the above

6. Refer to this portion of a specification sheet. Determine the values of reverse-gate-source voltage and gate current if the FET was forced to accept it.

A. 25 Vdc, –200 nAdc B. –25 Vdc, 10 mAdc C. –6 Vdc, –1.0 nAdc D. None of the above

7. At which of the following condition(s) is the depletion region uniform?

A. No bias B. VDS > 0 V C. VDS = VP

8. What is the ratio of ID / IDSS for VGS = 0.5 VP?

A. 0.25

B. 0.5

C. 1

D. 0

9. Referring to this transfer curve, determine ID at VGS = 2 V.

A. 0.444 mA B. 1.333 mA C. 0.111 mA D. 4.444 mA

10. Which of the following controls the level of ID?

A. VGS

B. VDS

C. IG

D. VDG

11. It is the insulating layer of ________ in the MOSFET construction that accounts for the very desirable high input impedance of the device.

A. SiO

B. GaAs

C. SiO2

D. HCl

12. The BJT is a ________ device. The FET is a ________ device.

A. bipolar, bipolar B. bipolar, unipolar C. unipolar, bipolar D. unipolar, unipolar

13. Referring to this transfer curve. Calculate (using Shockley's equation) VGS at ID = 4mA.

A. 2.54 V B. –2.54 V

C. –12 V

D. Undefined

14. The drain current will always be one-fourth of IDSS as long as the gate-to-source voltage is ________ the pinch-off value.

A. one-fourth B. one-half C. three-fourths D. None of the above

15. The transfer curve is not defined by Shockley's equation for the ________. A. JFET

B. depletion-type MOSFET C. enhancement-type MOSFET

D. BJT

16. What is the purpose of adding two Zener diodes to the MOSFET in this figure?

A. To reduce the input impedance B. To protect the MOSFET for

both polarities

C. To increase the input impedance

17. Referring to the following transfer curve, determine the level of VGS when the drain current is 20 mA.

A. 1.66 V B. –1.66 V C. 0.66 V D. –0.66 V

18. The region to the left of the pinch-off locus is referred to as the ________ region.

A. saturation B. cutoff

(13)

C. ohmic

D. All of the above

19. Refer to the following curves. Calculate ID at VGS = 1 V.

A. 8.167 mA B. 4.167 mA C. 6.167 mA D. 0.616 mA

20. Which of the following transistor(s) has (have) depletion and enhancement types?

A. BJT

B. JFET

C. MOSFET

21. The three terminals of the JFET are the ________, ________, and ________. A. gate, collector, emitter

B. base, collector, emitter C. gate, drain, source D. gate, drain, emitter

22. Which of the following is (are) the terminal(s) of a field-effect transistor (FET).

A. Drain

B. Gate

C. Source

D. All of the above

23. A BJT is a ________-controlled device. The JFET is a ________ -controlled device.

A. voltage, voltage B. voltage, current C. current, voltage D. current, current

24. How many terminals can a MOSFET have?

A. 2

B. 3

C. 4

D. 3 or 4

25. Refer to the following figure. Calculate VGS at ID = 8 mA for k = 0.278 × 10–2 A/V2.

A. 3.70 V B. 5.36 V C. 7.36 V D. 2.36 V

26. The level of VGSthat results in ID = 0 mA is defined by VGS = ________.

A. VGS(off)

B. VP

C. VDS

27. Which of the following FETs has the lowest input impedance?

A. JFET

B. MOSFET depletion-type C. MOSFET enhancement-type D. None of the above

28. Which of the following applies to MOSFETs?

A. No direct electrical connection

between the gate

terminal and the channel

B. Desirable high input impedance C. Uses metal for the gate, drain,

and source connections D. All of the above

29. At which of the following is the level of VDS equal to the pinch-off voltage? A. When ID becomes equal to IDSS B. When VGS is zero volts

C. IG is zero

D. All of the above

30. Which of the following represent(s) the cutoff region for an FET?

A. ID = 0 mA B. VGS= VP C. IG = 0

D. All of the above

31. Which of the following is (are) the advantage(s) of VMOS over MOSFETs?

A. Reduced channel resistance B. Higher current and power

ratings

C. Faster switching time D. All of the above

32. Hand-held instruments are available to measure ________ for the BJT.

A. βDC

B. IDSS C. VP

D. All of the above

33. Which of the following input impedances is not valid for a JFET? A. 1010

Ω

B. 109

Ω

C. 108Ω D. 1011

Ω

34. Refer to the following characteristic curve. Calculate the resistance of the FET at VGS = –0.25 V if ro = 10 k

Ω

.

A. 1.1378 k

Ω

B. 113.78

Ω

C. 11.378

Ω

D. 11.378 kΩ

35. Which of the following is (are) not an FET?

A. n-channel B. p-channel C. p-n channel

D. n-channel and p-channel

FET AMPLIFIERS

1. A common-gate amplifier is similar in configuration to which BJT amplifier? A. common-emitter

B. common-collector C. common-base D. emitter-follower

2. The theoretical efficiency of a class D amplifier is

A. 75%.

B. 85%.

C. 90%.

(14)

3. A common-source amplifier is similar in configuration to which BJT amplifier? A. common-base

B. common-collector C. common-emitter D. emitter-follower

4. Refer to this figure. If R6 opened, the signal at the drain of Q1 would

A. increase. B. decrease.

C. remain the same. D. distort.

5. Refer to this figure. Find the value of VD. A. 20 V B. 11 V C. 10 V D. 9 V 6. A BJT is a ________-controlled device. A. current B. voltage

7. Referring to this figure, calculate Avif rd= 19 kΩ.

A. –2.85

B. –3.26

C. –2.95

D. –3.21

8. A common-drain amplifier is similar in configuration to which BJT amplifier?

A. common-emitter B. common-collector C. common-base D. common-gate

9. Referring to this figure, calculate Av for yos = 58µS.

A. –7.29

B. –7.50

C. –8.05

D. –8.55

10. Refer to this figure. If Vin = 1 V p-p, the output voltage Voutwould be

A. undistorted.

B. clipped on the negative peaks. C. clipped on the positive peaks. D. 0 Vp-p

11. Use the following equation to calculate gm for a JFET having IDSS = 10 mA, VP = –5 V, and VGSQ = –2.5 V.





 

_|



_

_{| [}



_



_

]

A. 2 mS B. 3 mS C. 4 mS D. 5 mS

12. For what value of IDis gm equal to 0.5 gm0?

A. 0 mA

B. 0.25 IDSS C. 0.5 IDSS D. IDSS

13. Refer to this figure. If Vin= 20 mV p-p what is the output voltage?

A. 176 mV p-p B. 88 mVp-p C. 48 mVp-p D. 24 mVp-p

14. Referring to the following figure, calculate gm for VGSQ = –1.25 V.

A. 2 mS

B. 2.5 mS C. 2.75 mS D. 3.25 mS

15. Referring to this figure, calculate the value of RD if the ac gain is 10. Assume VGSQ = ¼Vp.

A. 2.2 kΩ

B. 2.42 kΩ C. 2.62 kΩ D. 2.82 kΩ

16. Where do you get the level of gm and rd for an FET transistor?

A. from the dc biasing arrangement

B. from the specification sheet C. from the characteristics D. All of the above

17. The class D amplifier uses what type of transistors?

(15)

B. BJTs

C. MOSFETs

D. any of the above

18. What is (are) the function(s) of the coupling capacitors C1 and C2 in an FET circuit?

A. to create an open circuit for dc analysis

B. to isolate the dc biasing arrangement from the applied signal and load

C. to create a short-circuit equivalent for ac analysis

D. All of the above

19. An FET is a ________-controlled device.

A. current B. voltage

20. What is the input resistance (Rin(source)) of a common-gate amplifier? A. Rs

B. (1+ gm) || Rs C. 1 / gm

21. There is a ________º phase inversion between gate and source in a source follower.

A. 0 @

B. 90

C. 180

22. Refer to this figure. If C4 opened, the signal voltage at the drain of Q1 would

23. Referring to this figure, find Zo if yos= 20µS.

A. 1.85 kΩ B. 1.92 kΩ C. 2.05 kΩ D. 2.15 kΩ

24. Which of the following is a required condition to simplify the equations for Zo and Av for the self-bias configuration? A. rd≤10RD

B. rd = RD C. rd≥ 10RD

25. The steeper the slope of the ID versus VGS curve, the ________ the level of gm. A. less

B. same

C. greater

26. What is the typical value for the input impedance Zi for JFETs?

A. 100 kΩ

B. 1 MΩ

C. 10 MΩ

D. 1000 MΩ

27. MOSFETs make better power switches than BJTs because they have A. lower turn-off times.

B. lower on-state resistance.

C. a positive temperature

coefficient.

D. all of the above

28. When VGS = 0.5 Vp gm is ________ the maximum value.

A. one-fourth B. one-half C. three-fourths

29. MOSFET digital switching is used to produce which digital gates?

A. inverters B. NOR gates C. NAND gates D. all of the above

30. Referring to the transfer

characteristics shown below, calculate gm at VGSQ = –1 V.

A. 2 mS

B. 3 mS

C. 4 mS

D. 5 mS

31. Which type of FETs can operate with a gate-to-source Q-point value of 0 V? A. JFET

B. E-MOSFET

C. D-MOSFET

32. On which of the following parameters does rd have no or little impact in a source-follower configuration?

A. Zi

B. Zo

C. Av

D. All of the above

33. Refer to this figure. For midpoint biasing, ID would be

A. 10 mA. B. 7.5 mA.

C. 5 mA.

D. 2.5 mA.

34. Class D amplifiers differ from all other classes of amplifiers because A. the output transistors are

operated as switches.

B. of their very low input capacitance.

C. of their high-frequency response capabilities.

(16)

35. Refer to this figure. If R7 were to decrease in value, Voutwould

C. remain the same. D. distort

36. Refer to this figure. If ID = 4 mA, find the value of VGS.

A. 10.8 V

B. 6 V

C. –0.7 V

D. –6 V

37. Which FET amplifier(s) has (have) a phase inversion between input and output signals?

A. common-gate B. common-drain C. common-source D. all of the above

38. What common factor determines the voltage gain and input resistance of a common-gate amplifier?

A. RD

B. RL

C. gm

39. Referring to the figure below, determine the output impedance for VGS = –3 V at VDS = 5 V.

A. 100 kΩ

B. 80 kΩ

C. 25 kΩ

D. 5 kΩ

40. Referring to this figure, calculate Zo if rd= 19 kΩ.

A. 1.75 kΩ B. 1.81 kΩ C. 1.92 kΩ D. 2.00 kΩ

41. Referring to this figure, calculate Zi if rd= 19 kΩ.

A. 2.42 MΩ

B. 2.50 MΩ

C. 2.53 MΩ

D. 2.59 MΩ

42. For the fixed-bias configuration, if rD < 10 RD ,

then Z

o

=

________.

A. RD

B. RD|| rD C. RG

D. -gm · (RD|| rD

)

43. Referring to this figure, obtain gm for ID = 6 mA.

A. 2.83 mS B. 3.00 mS C. 3.25 mS D. 3.46 mS

44. Referring to this figure, calculate Zo for VGSQ = –3.2 V.

A. 362.52 Ω B. 340.5 Ω C. 420.5 Ω

D. 480.9 Ω

45. The more horizontal the characteristic curves on the drain

characteristics, the ________ the output impedance.

A. less

B. same

C. greater

46. Refer to this figure. If gm = 4000 mS and a signal of 75 mVrms is applied to the gate, calculate the p-p output voltage.

A. 990 mV B. 1.13 V p-p C. 2.8 Vp-p D. 990 Vp-p

47. Refer to this figure. The approximate value of Rin is

A. 100 MΩ. B. 1.5 kΩ. C. 3.3 kΩ. D. 48 MΩ.

48. Which of the following is (are) related to depletion-type MOSFETs? A. VGSQ can be negative, zero, or

(17)

B. gm can be greater or smaller than gm0.

C. ID can be larger than IDSS. D. All of the above

49. Refer to this figure. If C2 shorted, Vout would

50. The input resistance at the gate of a FET is extremely

A. high. B. low.

51. Determine the value for RD if the ac gain is 8.

A. 1.51 kΩ B. 1.65 kΩ C. 1.85 kΩ D. 2.08 kΩ

52. Referring to this figure, calculate Zi for yos = 20 µS. Assume VGSQ= −2.2V.

A. 300.2 Ω B. 330.4 Ω C. 340.5 Ω D. 350.0 Ω

53. FET amplifiers provide ________. A. excellent voltage gain

B. high input impedance C. low power consumption D. All of the above

54. CMOS digital switches use

A. n-channel and p-channel D-MOSFETs in series.

B. n-channel and p-channel D-MOSFETs in parallel.

C. n-channel and p-channel E-MOSFETs in series.

D. n-channel and p-channel E-MOSFETs in parallel.

55. What is the range of gm for JFETs? A. 1 µS to 10µS

B. 100µS to 1000 µS C. 1000 µS to 5000 µS D. 10000 µS to 100000 µS

56. Calculate gm and rd if yfs = 4 mS and yos= 15ΩS.

A. 4 mS, 66.7 kΩ B. 4 mS, 15 kΩ C. 66.7 kΩ, 4 mS D. None of the above

57. What limits the signal amplitude in an analog MOSFET switch?

A. the switch input capacitance B. VGS(th)

C. the switch's power handling D. VDS

58. Input resistance of a common-drain amplifier is

A. RG || RIN(gate). B. RG + RIN(gate).

C. RG.

D. RIN(gate).

59. Refer to this Figure. If Vin was increased in amplitude a little, the signal voltage at the source of Q2 would

60. Refer to this figure. If VGS = –6 V, calculate the value of RS that will provide this value.

A. 2.2 kΩ

B. 1.2 kΩ

C. 600 kΩ

D. 100 kΩ

61. A JFET cascade amplifier employs A. 2 common-gate amplifiers. B. 2 common-source amplifiers. C. 1 common-gate and 1

common-source amplifier. D. 1 gate and 1

common-drain amplifier.

62. E-MOSFETs are generally used in switching applications because

A. of their very low input capacitance.

B. of their threshold

characteristic (VGS(th)).

C. of their high-frequency response capabilities.

D. of their power handling.

63. For an FET small-signal amplifier, one could go about troubleshooting a circuit by ________.

A. viewing the circuit board for poor solder joints

B. using a dc meter

C. applying a test ac signal D. All of the above

64. The E-MOSFET is quite popular in ________ applications.

A. digital circuitry B. high-frequency C. buffering

D. All of the above

65. Referring to this figure, calculate Av if yos = 20 µS.

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A. –3.48

B. –3.56

C. –3.62

D. –4.02

66. Referring to this figure, calculate Zo if yos = 40µS.

A. 2.92 kΩ B. 3.20 kΩ C. 3.25 kΩ D. 3.75 kΩ

67. In a common-source amplifier, the purpose of the bypass capacitor, C2, is to A. keep the source effectively at

ac ground.

B. provide a dc path to ground. C. provide coupling to the input. D. provide coupling to the load. 68. Refer to this figure. The voltage gain is

A. 1.2. B. 2.4. C. 4.4. D. 8.8.

69. Refer to this figure. If ID = 4 mA, IDSS = 16 mA, and VGS(off)= –8 V, find VDS.

A. 19.2 V B. –6 V C. 10.8 V D. 30 V 70. If ID = IDSS / 2, gm = ________ gmo. A. 1 B. 0.707 C. 0.5

BJT AND FET FREQUENCY

RESPONSE

1. A change in frequency by a factor of ________ is equivalent to 1 octave.

A. 2

B. 10

C. 5

D. 20

2. What is the ratio of the capacitive reactance XCS to the input resistance RI of the input RC circuit of a single-stage BJT amplifier at the low-frequency cutoff?

A. 0.25 B. 0.50 C. 0.75

D. 1.0

3. For which of the following frequency region(s) can the coupling and bypass capacitors no longer be replaced by the short-circuit approximation?

A. Low-frequency B. Mid-frequency C. High-frequency D. All of the above

4. Determine the lower cutoff frequency of this network.

A. 15.8 Hz

B. 46.13 Hz C. 238.73 Hz D. 1575.8 Hz

5. The smaller capacitive elements of the design will determine the ________ cutoff frequencies.

A. low

B. mid

C. high

6. What is the range of the capacitor Cds? A. 0.01 to 0.1 pF

B. 0.1 to 1 pF C. 0.1 to 1 nF D. 0.1 to 1 F

7. An amplifier rated at 30-W output is connected to a 5- speaker. Calculate the input voltage for the rated output if the amplifier voltage gain is 20 dB.

A. 1.225 mV B. 12.25 mV C. 122.5 mV D. 1.225 V

8. A 3-dB drop in hfe will occur at a frequency defined by ________.

A. f α B. f β

C. 1

D. 2

9. An amplifier rated at 30-W output is connected to a 5- speaker. Calculate the input power required for full power output if the power gain is 20 dB.

A. 3 mW

B. 30 mW

C. 300 mW

D. 3 W

10. The larger capacitive elements of the design will determine the ________ cutoff frequency.

A. low

B. mid

C. high

11. Which of the following elements is (are) important in determining the gain of the system in the high-frequency region?

A. Interelectrode capacitances B. Wiring capacitances

C. Miller effect capacitance D. All of the above

12. The input power to a device is 10,000 W at 1000 V. The output power is 500 W, and the output impedance is 100Ω. Find the voltage gain in decibels.

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A. –30.01 dB B. –20.0 dB C. –13.01 dB D. –3.01 dB

13. By what factor does an audio level change if the power level changes from 4 W to 4096 W?

A. 2

B. 4

C. 6

D. 8

14. For audio systems, the reference level is generally accepted as ________.

A. 1 mW

B. 1 W

C. 10 mW

D. 100 mW

15. What is the range of the capacitors Cgsand Cgd?

A. 1 to 10 pF B. 1 to 10 nF C. 1 to 10 F D. 1 to 10 F

16. For the low-frequency response of a BJT amplifier, the maximum gain is where ________ .

A. RB= 0 Ω B. RC= 0 Ω C. RE= 0 Ω

17. In the input RC circuit of a single-stage BJT, by how much does the base voltage lead the input voltage at the cutoff frequency in the low-frequency region?

A. About 0º

B. 45º

C. About 90º

18. What is the normalized gain expressed in dB for the cutoff frequencies?

A. –3 dB

B. +3 dB

C. –6 dB

D. –20 dB

19. Which of the low-frequency cutoffs determined by CS, CC, or CE will be the predominant factor in determining the low-frequency response for the complete system?

A. lowest B. middle C. highest

20. Determine the break frequency for this circuit.

A. 15.915 Hz B. 159.15 Hz C. 31.85 Hz D. 318.5 Hz

21. What is the ratio of the common logarithm of a number to its natural logarithm?

A. 0.435

B. 2

C. 2.3

D. 3.2

22. Which of the following configurations does (do) not involve the Miller effect capacitance?

A. Common-emitter B. Common-base C. Common-collector D. All of the above

23. What magnitude voltage gain corresponds to a decibel gain of 50? A. 31.6238

B. 316.228 C. 3162.38 D. 31623.8

24. By what other name(s) are the cutoff frequencies in a frequency response plot called?

A. Corner frequency B. Break frequency C. Half-power frequency D. All of the above

25. The ________-frequency response of a transformer-coupled system is calculated primarily by the stray capacitance between the turns of the primary and secondary windings.

A. low B. mid C. high 26. logea = ________ log10a A. 2.3 B. 2.718 C. e D. 1.414

27. In the hybrid π or Giacolet to model, which one of the following does rb include?

A. Base spreading resistance B. Base contact

C. Base bulk

D. All of the above

28. What is the ratio of the output voltage to the input voltage at the cutoff frequencies in a normalized frequency response plot?

A. 0.25 B. 0.50 C. 0.707

D. 1

29. Which of the following statements is true for a square-wave signal?

A. It is composed of both even and odd harmonics.

B. It is composed only of odd harmonics.

C. It is composed only of even harmonics.

D. The harmonics waveforms are also square waves.

30. A change in frequency by a factor of ________ is equivalent to 1 decade.

A. 2

B. 10

C. 5

D. 20

31. Which of the following capacitors is (are) included in Ci for the high-frequency region of a BJT or FET amplifier?

A. Input wiring capacitance Cw1

B. The transition capacitance (Cbe/

Cqs)

C. Miller capacitance CM1

D. All of the above

32. In the input RC circuit of a single-stage BJT, by how much does the base voltage lead the input voltage for frequencies much larger than the cutoff frequency in the low-frequency region? A. About 0º

B. 45º

C. About 90º

33. In the ________-frequency region, the capacitive elements of importance are the interelectrode (between terminals) capacitances internal to the active device and the wiring capacitance between the leads of the network.

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A. low

B. mid

C. high

34. What is the ratio of the output power to the input power at the cutoff frequencies in a normalized frequency response plot?

A. 0.25 B. 0.50 C. 0.707

D. 1

BASIC OP AMP CIRCUITS

1. A Schmitt trigger is

A. a comparator with only one trigger point.

B. a comparator with hysteresis. C. a comparator with three trigger

points.

D. none of the above.

2. Refer to the given figure. This circuit is known as

A. a noninverting amplifier. B. a differentiator.

C. an integrator.

D. a summing amplifier.

3. The output of a Schmitt trigger is a A. pulse waveform.

B. sawtooth waveform. C. sinusoidal waveform. D. triangle waveform.

4. Refer to the given figure. This circuit is known as

A. a noninverting amplifier. B. a differentiator.

C. an integrator.

D. a summing amplifier.

5. Refer to the given figure. A square-wave input is applied to this amplifier.

The output voltage is most likely to be

A. a square wave. B. a triangle wave. C. a sine wave. D. no output.

6. Refer to the given figure. What is the output voltage?

A. 2 V

B. –2 V

C. +Vsat

D. –Vsat

7. If an op-amp comparator has a gain of 100,000, an input difference of 0.2 mV above reference, and a supply of ± 12 V, the output will be

A. 20 V. B. 12 V. C. 10 V. D. 15 V.

8. A comparator with a Schmitt trigger has

A. two trigger levels. B. a fast response. C. a slow response. D. one trigger level.

9. Refer to the given figure. Determine the upper trigger point.

A. V(out)max B. –V(out)max C. –1.41 V D. +1.41 V

10. In a(n) ________, when the input voltage exceeds a specified reference voltage, the output changes state. A. integrator

B. differentiator

C. summing amplifier D. comparator

11. Refer to the given figure. If Vin = 5 V, the rate of change of the output voltage in response to a single pulse input is:

A. 15.2 mV/μs B. 1.52 V/μs C. 1.52 mV/μs D. 15.2 V/μs

12. In a flash A/D converter, the priority encoder is used to

A. select the first input.

B. select the highest value input. C. select the lowest value input. D. select the last input.

13. What circuit produces an output that approximates the area under the curve of an input function?

A. integrator B. differentiator C. summing amplifier D. comparator

14. An op-amp has an open-loop gain of 90,000. Vsat = ±13 V. A differential voltage of 0.1 Vp-pis applied between the inputs. What is the output voltage? A. 13 V

B. –13 V

C. 13 Vp-p D. 26 Vp-p

15. Refer to the given figure. Determine the output voltage.

A. 1 V

B. –1 V

C. +Vsat D. –Vsat

16. A good example of hysteresis is a(n) A. AM radio.

B. thermostat. C. alarm clock. D. none of the above