Semiconductors Past Paper PDF

PART 1 SEMICONDUCTORS SPECIAL PURPOSE DIODES BIPOLAR JUNCTION TRANSISTORS BJT DEVICES BJT AMPLIFIERS FET DEVICES FET AMPLIFIERS BJT AND FET FREQUENCY RESPONSE BASIC OP AMP CIRCUITS SEMICONDUCTOR DIODES DIODE APPLICATIONS TRAN...

PART 1 SEMICONDUCTORS SPECIAL PURPOSE DIODES BIPOLAR JUNCTION TRANSISTORS BJT DEVICES BJT AMPLIFIERS FET DEVICES FET AMPLIFIERS BJT AND FET FREQUENCY RESPONSE BASIC OP AMP CIRCUITS SEMICONDUCTOR DIODES DIODE APPLICATIONS TRANSISTOR BIAS CIRCUITS DC BIASING BJTS FIELD EFFECT TRANSISTORS DC BIASING FETS  INDIABIX 1 SEMICONDUCTORS 9. An n-type semiconductor material 16. A reverse-biased diode has the A. is intrinsic. ________ connected to the positive side 1. A silicon diode measures a low value B. has trivalent impurity atoms of the source, and the ________ of resistance with the meter leads in added. connected to the negative side of the both positions. The trouble, if any, is C. has pentavalent impurity source. A. the diode is open. atoms added. A. cathode, anode B. the diode is shorted to ground. D. requires no doping. B. cathode, base C. the diode is internally shorted. C. base, anode 10. For a forward-biased diode, as D. the diode is working correctly. D. anode, cathode temperature is ________, the forward 2. Single-element semiconductors are current ________ for a given value of 17. What types of impurity atoms are characterized by atoms with ____ forward voltage. added to increase the number of valence electrons. A. decreased, increases conduction-band electrons in intrinsic A. 3 B. increased, increases silicon? B. 4 C. increased, decreases A. bivalent C. 5 D. decreased, decreases B. octavalent D. 2 C. pentavalent 11. Which statement best describes D. trivalent 3. Under normal conditions a diode an insulator? E. none of the above conducts current when it is A. A material with many free A. reverse-biased. electrons. 18. What factor(s) do(es) the barrier B. forward-biased. B. A material doped to have some potential of a pn junction depend on? C. avalanched. free electrons. A. type of semiconductive D. saturated. C. A material with few free material electrons. B. the amount of doping 4. A diode conducts when it is forward- D. No description fits. C. the temperature biased, and the anode is connected to D. all of the above the ________ through a limiting resistor. 12. Effectively, how many valence E. type of semiconductive A. positive supply electrons are there in each atom within a material and the amount of B. negative supply silicon crystal? doping but not the temperature C. cathode A. 2 B. 4 19. An atom is made up of D. anode C. 8 A. protons. 5. As the forward current through a D. 16 B. neutrons. silicon diode increases, the internal C. electrons. resistance 13. The boundary between p-type D. all of the above A. increases. material and n-type material is called B. decreases. A. a diode. 20. Reverse breakdown is a condition in C. remains the same. B. a reverse-biased diode. which a diode C. a pn junction. A. is subjected to a large reverse 6. The movement of free electrons in a D. a forward-biased diode. voltage. conductor is called B. is reverse-biased and there is a A. voltage. 14. You have an unknown type of diode small leakage current. B. current. in a circuit. You measure the voltage C. has no current flowing at all. C. recombination. across it and find it to be 0.3 V. The D. is heated up by large amounts D. equilibrium. diode might be of current in the forward direction. A. a silicon diode. 7. For a forward-biased diode, the barrier B. a germanium diode. potential ________ as temperature 21. There is a small amount of current C. a forward-biased silicon diode. increases. across the barrier of a reverse-biased D. a reverse-biased germanium A. decreases diode. This current is called diode. B. remains constant A. forward-bias current. C. increases 15. An ideal diode presents a(n) B. reverse breakdown current. ________ when reversed-biased and a(n) C. conventional current. 8. The wide end arrow on a schematic ________ when forward-biased. D. reverse leakage current. indicates the ________ of a diode. A. open, short A. ground 22. As the forward current through a B. short, open B. direction of electron flow silicon diode increases, the voltage C. open, open C. cathode across the diode D. short, short D. anode A. increases to a 0.7 V maximum. B. decreases.  INDIABIX 1 C. is relatively constant. C. the value of dc voltages for D. decreases and then increases. the device to operate properly. 23. Doping of a semiconductor material D. the status of the diode. means A. that a glue-type substance is added to hold the material together. SPECIAL- PURPOSE A. increase. B. decrease. B. that impurities are added to DIODES C. remain the same. increase the resistance of the material. 1. Schottky diodes are also known as 7. What kind of diode is formed by C. that impurities are added to A. PIN diodes. joining a doped semiconductor region decrease the resistance of B. hot carrier diodes. with a metal? the material. C. step-recovery diodes. A. laser D. that all impurities are removed D. tunnel diodes. B. tunnel to get pure silicon. C. pin 2. Zener diodes with breakdown D. Schottky 24. The forward voltage across a voltages less than 5 V operate conducting silicon diode is about predominantly in what type of 8. Refer to this figure. Which symbol is A. 0.3 V. breakdown? correct for a zener diode? B. 1.7 V. A. avalanche C. 0.7 V. B. zener D. 0.7 V. C. varactor 25. The most common type of diode D. Schottky failure is a(n) ________. 3. The Schottky diode is used A. open A. in high-power circuits. A. a B. short B. in circuits requiring negative B. b C. resistive resistance. C. c C. in very fast-switching circuit D. d 26. What occurs when a conduction- D. in power supply rectifiers E. e band electron loses energy and falls back into a hole in the valence band? 4. You have an application for a diode to 9. Which diode employs graded doping? A. doping be used in a tuning circuit. A type of A. zener B. recombination diode to use might be B. LED C. generation A. an LED. C. tunnel B. a Schottky diode. D. step-recovery 27. The maximum number of electrons in each shell of an atom is C. a Gunn diode. 10. Refer to this figure. Identify the A. 2. D. a varactor. Schottky diode. 2 B. 2n where n is the number of 5. Refer to this figure. Which symbol is the shell. correct for an LED? C. 4. D. 8. 28. A silicon diode is forward-biased. You measure the voltage to ground from A. a the anode at ________, and the voltage B. b from the cathode to ground at A. a C. c ________. B. b D. d A. 0 V, 0.3 V C. c E. e B. 2.3 V, 1.6 V D. d 11. LEDs are made out of C. 1.6 V, 2.3 V E. e A. silicon. D. 0.3 V, 0 V 6. Refer to this figure. If V IN increases, IZ B. germanium. 29. The term bias in electronics usually will C. gallium. means D. silicon and germanium, but not A. the value of ac voltage in the gallium. signal. 12. The normal operating region for a B. the condition of current zener diode is the through a pn junction. A. forward-bias region.  INDIABIX 1 B. reverse-bias region. 18. The process of emitting photons B. decrease. C. zero-crossing region. from a semiconductive material is called C. remain the same. D. reverse-breakdown region. A. photoluminescence. 25. Zener diodes with breakdown B. gallium arsenide. 13. Refer to this figure. If VIN attempts to voltages greater than 5 V operate C. electroluminescence. increase, VR will predominantly in what type of D. gallium phosphide. breakdown? 19. An 8.2 V zener has a resistance of A. avalanche B. zener terminals when the current is 25 mA is C. varactor A. 8.2 V. D. Schottky A. increase. B. 125 mV. 26. Back-to-back varactor diodes are B. decrease. C. 8.325 V. used for what reason? C. remain the same. D. 8.075 V. A. over-voltage protection 14. An LED is forward-biased. The diode 20. What diode operates only with B. a wider tuning range should be on, but no light is showing. A majority carriers? C. to eliminate harmonic possible trouble might be A. laser distortion A. the diode is open. B. tunnel D. no reason; only zeners are used B. the series resistor is too small. C. Schottky in a back-to-back C. none. The diode should be off if D. step-recovery configuration forward-biased. 21. Refer to this figure. Which symbol is 27. A tunnel diode is used D. the power supply voltage is too correct for a photodiode? A. in high-power circuits. high. B. in circuits requiring negative 15. A 6.2 V zener is rated at 1 watt. The resistance. maximum safe current the zener can C. in very fast-switching circuits. carry is D. in power supply rectifiers. A. 1.61 A. 28. What type of diode is commonly B. 161 mA. A. a used in electronic tuners in TVs? C. 16.1 mA. B. b A. varactor D. 1.61 mA. C. c B. Schottky 16. Refer to this figure. Find the tunnel D. d C. LED diode symbol. E. e D. Gunn 22. What type of diode maintains a 29. A laser diode normally emits constant current? A. coherent light. A. LED B. monochromatic light. B. zener C. coherent and monochromatic C. current regulator light. A. a D. pin D. neither coherent nor B. b E. none of the above monochromatic light. C. c 23. What diode is used in seven-segment 30. A varactor is a pn junction diode that D. d displays? always operates in ________-bias and is E. e A. zener doped to ________ the inherent 17. Refer to this figure. If the load current B. LED capacitance of the depletion region. increases, IR will _____ and IZ will _____. C. laser A. forward, maximize D. Schottky B. reverse, maximize C. reverse, minimize 24. Refer to this figure. If VIN decreases, IR will D. forward, minimize A. remain the same, increase BIPOLAR JUNCTION B. decrease, remain the same TRANSISTORS C. increase, remain the same D. remain the same, decrease 1. Refer to this figure. Determine the A. increase. minimum value of IB that will produce saturation.  INDIABIX 1 A. 9.2 V 14. Refer to this figure. The value of VBE B. 9.9 V is: 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 A. 0.25 mA C. saturation and cutoff B. 5.325 µA D. none of the above A. 0.6 V C. 1.065 µA D. 10.425 µA 8. The term BJT is short for B. 0.7 V A. base junction transistor. C. 1.2 V 2. A transistor amplifier has a voltage B. binary junction transistor. D. 0.079 V gain of 100. If the input voltage is 75 mV, C. both junction transistor. 15. What are the two types of bipolar the output voltage is: D. bipolar junction transistor junction transistors? A. 1.33 V B. 7.5 V 9. For a silicon transistor, when a base- A. npn and pnp C. 13.3 V emitter junction is forward-biased, it has B. pnn and nnp D. 15 V a nominal voltage drop of C. ppn and nnp A. 0.7 V. D. pts and stp 3. Refer to this figure. If VCE = 0.2 V, IC(sat) B. 0.3 V. is: 16. In this circuit DC= 100 and VIN = 8 V. C. 0.2 V. The value of RB that will produce D. VCC. saturation is: 10. A certain transistor has IC = 15 mA and IB = 167µA; DC is: A. 15 B. 167 C. 0.011 D. 90 A. 0.05 mA 11. Refer to this figure. The value of VCE B. 2.085 mA is: C. 1.065 mA A. 92 k D. 7.4 mA B. 9.1 M 4. What is the ratio of IC to IB? C. 100 k A. D. 150 k DC B. hFE 17. The value of DC C. DC A. is fixed for any particular D. DC or hFE, but not DC transistor. 5. For normal operation of a pnp BJT, the B. varies with temperature. A. 9.9 V C. varies with IC. base must be ________ with respect to B. 9.2 V D. varies with temperature and the emitter and ________ with respect C. 0.7 V IC. to the collector. D. 19.3 V A. positive, negative 18. A transistor data sheet usually B. positive, positive 12. What does DC vary with? identifies DC as C. negative, positive A. IC A. hre. D. negative, negative B. ºC B. hFE. C. both IC and ºC C. IC. 6. Refer to this figure. The value of VBC is: D. IC , but not ºC D. VCE. 13. A BJT has an IB of 50µA and a of 19. What is the ratio of IC to IE? DC A. 75; IC is: DC B. DC / ( DC + 1) A. 375 mA C. DC B. 37.5 mA D. either DC / ( DC + 1) or DC, but C. 3.75 mA not DC D. 0.375 mA  INDIABIX 1 20. Refer to this figure. The value of DC 27. What is (are) common fault(s) in a 4. For what kind of amplifications can = 100 and VIN = 8 V. Determine IC(sat). BJT-based circuit? the active region of the common- A. opens or shorts internal to the emitter configuration be used? transistor A. Voltage B. open bias resistor(s) B. Current C. external opens and shorts on C. Power the circuit board D. All of the above D. all of the above 5. In the active region, while the 28. The dc load line on a family of collector-base junction is ________- A. 18 mA collector characteristic curves of a biased, the base-emitter is ________- B. 7.92 mA transistor shows the biased. C. 1.8 mA A. saturation region. A. forward, forward D. 8 µA B. cutoff region. B. forward, reverse 21. Which of the following is true C. active region. C. reverse, forward for an npn or pnp transistor? D. all of the above D. reverse, reverse A. I E = IB + IC 29. Refer to this figure. Determine the 6. A transistor can be checked using a(n) B. IB = IC+ IE minimum value of VIN from the following ________. C. IC = IB + IE that will saturate this transistor. A. curve tracer D. none of the above B. digital meter 22. What is the order of doping, from C. ohmmeter heavily to lightly doped, for each region? D. Any of the above A. base, collector, emitter 7. What range of resistor values would B. emitter, collector, base you get when checking a transistor for C. emitter, base, collector forward- and reverse-biased conditions D. collector, emitter, base by an ohmmeter? 23. In what range of voltages is the A. 1 transistor in the linear region of its A. 13.21 V operation? B. 12.51 V B. Exceeding 100 k , 100 to a few A. 0 < VCE C. 0.7 V k B. 0.7 < VCE < VCE(max) D. 9.4 V C. Exceeding 100 k , exceeding C. VCE(max) > VCE 100 k D. none of the above D. 100 to a few k , 100 to a 24. The magnitude of dark current in a few k phototransistor usually falls in what BJT DEVICES range? 8. Calculate minority current ICO if IC = A. mA 1. How much is the base-to-emitter 20.002 mA and IC majority = 20 mA. B. voltage of a transistor in the "on" state? A. 20 µA C. nA A. 0V B. 0.002 µA D. pA B. 0.7 V C. 2 nA C. 0.7 mV D. 2 µA 25. A 35 mV signal is applied to the base D. Undefined of a properly biased transistor with an r'e 9. What is (are) the component(s) of = 8 and RC = 1 k. The output signal 2. How many layers of material does a electrical characteristics on the voltage at the collector is: transistor have? specification sheets? A. 3.5 V A. 1 A. On B. 28.57 V B. 2 B. Off C. 4.375 mV C. 3 C. Small-signal characteristics D. 4.375 V D. 4 D. All of the above 26. What is (are) general-purpose/small- 3. Which of the following equipment can 10. In which region are both the signal transistors case type(s)? check the condition of a transistor? collector-base and base-emitter A. TO-18 A. Current tracer junctions forward-biased? B. TO-92 B. Digital display meter (DDM) A. Active C. TO-39 C. Ohmmeter (VOM) B. Cutoff D. TO-52 D. All of the above C. Saturation E. all of the above D. All of the above  INDIABIX 1 11. An example of a pnp silicon transistor A. Common-base is a 2N4123. B. Common-collector A. True C. Common-emitter B. False D. Emitter-collector 12. Which of the following is (are) the 25. dc for this set of collector terminal(s) of a transistor? characteristics is within ________ A. Emitter percent of ac. B. Base A. 100 C. Collector B. 116 D. All of the above C. 50 D. 110 13. Use this table of collector characteristics to calculate ac at VCE = 15 19. Which of the following can be V and IB = 30 µA. obtained from the last scale factor of a curve tracer? A. hFE A. 2 B. dc B. 5 C. ac C. 7 D. ac D. 10 20. Calculate ac for IC = 15 mA and VCE = 26. Which of the following regions is 5 V. (are) part of the output characteristics of A. 100 a transistor? B. 106 A. Active C. 50 B. Cutoff D. 400 C. Saturation 14. Which of the following D. All of the above configurations can a transistor set up? 27. How many individual pnp silicon A. Common-base transistors can be housed in a 14-pin B. Common-emitter plastic dual-in-line package? C. Common-collector A. 4 D. All of the above B. 7 A. 200 C. 10 15. What does a reading of a large or B. 180 D. 14 small resistance in forward- and reverse- C. 220 biased conditions indicate when 28. In what decade was the first D. None of the above checking a transistor using an transistor created? ohmmeter? 21. dc = ________ A. 1930s A. Faulty device A. IB / IE B. 1940s B. Good device B. IC / IE C. 1950s C. Bad ohmmeter C. I C / IB D. 1960s D. None of the above D. None of the above 29. Most specification sheets are broken 16. Determine the value of when = 22. How many carriers participate in the down into ________. 100. injection process of a unipolar device? A. maximum ratings A. 1.01 A. 1 B. thermal characteristics B. 101 B. 2 C. electrical characteristics C. 0.99 C. 0 D. All of the above D. Cannot be solved with the D. 3 30. For a properly biased pnp transistor, information provided 23. What are the ranges of the ac input let IC = 10 mA and IE = 10.2 mA. What is 17. Transistors are ________-terminal and output resistance for a common- the level of IB? devices. base configuration? A. 0.2 A A. 2 A. B. 200 mA B. 3 B. 50 k 1 M , 10 100 C. 200 µA C. 4 C. 10 100 k , 50 1k D. 20.2 ma D. 5 D. None of the above 31. What is (are) the component(s) of 18. Calculate dc at VCE = 15 V and IB = 30 24. What is the most frequently most specification sheets provided by µA. encountered transistor configuration? the manufacturer?  INDIABIX 1 A. Maximum ratings 10. What is the most important r B. Thermal characteristics parameter for amplifier analysis? C. Electrical characteristics A. rb D. All of the above B. rc C. re dc equal to? A. IB / IE 11. An emitter-follower is also known as: B. IC / IE A. common-emitter amplifier. C. I C / IB B. common-base amplifier. D. None of the above A. 2 mA C. common-collector amplifier. B. 4 mA D. Darlington pair. 33. List the types of bipolar junction transistors. C. 5 mA 12. The ________ model fails to account A. ppn, npn D. 6 mA for the output impedance level of the B. pnp, npn 5. Which of the following is referred to as device and the feedback effect from C. npp, ppn the reverse transfer voltage ratio? output to input. D. nnp, pnp A. hi A. hybrid equivalent B. hr B. re 34. What is the ratio of the total width to C. hf C. that of the center layer for a transistor? D. ho D. Thevenin A. 1:15 B. 1:150 6. Which of the following conditions 13. Refer to this figure. Calculate the C. 15:1 must be met to allow the use of the value of VB. D. 150:1 approximate approach in a voltage- 35. Which component of the collector divider bias configuration? current IC is called the leakage current? A. re > 10R2 A. Majority B. re > 10R2 B. Independent C. re < 10R2 C. Minority D. re < 10R2 D. None of the above 7. Refer to this figure. Determine the value of Av. BJT AMPLIFIERS A. 5V B. 3.7 V 1. The current gain for the Darlington C. 20 V connection is ________. D. 3V A. 1· ( 2 /2) 14. You have a need to apply an B. 1· 2 amplifier with a very high power gain. C. 1/ 2 Which of the following would you D. 1· ( 2 -1) choose? A. 49.6 2. Which of the following configurations B. 5 A. common-collector has the lowest output impedance? C. 100 B. common-base A. Fixed-bias D. 595 C. common-emitter B. Voltage-divider D. emitter-follower C. Emitter-follower 8. For a common-emitter amplifier, the purpose of swamping is 15. What is the voltage gain of a D. None of the above feedback pair connection? A. to minimize gain. 3. Which of the h-parameters B. to reduce the effects of r'e A. 1 corresponds to re in a common-base C. to maximize gain. B. 1 configuration? D. no purpose. C. 100 A. hib D. 100 B. hfb 9. What is the typical value of the current gain of a common-base 16. A common-emitter amplifier has C. hrb ________ voltage gain, ________ current D. hob configuration? A. Less than 1 gain, ________ power gain, and 4. Refer to this figure. Find the value of B. Between 1 and 50 ________ input impedance. IE. C. Between 100 and 200 A. high, low, high, low D. Undefined  INDIABIX 1 B. high, high, high, low A. The output and input voltages D. the difference of the two input C. high, high, high, high are 180º out of phase. voltages. D. low, low, low, high B. Gain is smaller than 1. 30. The ________ model suffers from C. Gain is larger than 1. 17. What is the range of the input being limited to a particular set of D. None of the above impedance of a common-base operating conditions if it is to be configuration? 24. For the common-emitter fixed-bias considered accurate. A. A few ohms to a maximum of configuration, there is a ________ phase A. hybrid equivalent 50 shift between the input and output B. re B. 1 k to 5 k signals. C. C. 100 k to 500 k A. 0º D. Thevenin D. 1 M to 2 M B. 45º 31. Under which of the following C. 90º 18. The advantage that a Sziklai pair has condition(s) is the current gain Av ? D. 180º over a Darlington pair is A. ro 10RC A. higher current gain. 25. Which one of the following B. RB 10re B. less input voltage is needed to configurations has the lowest input C. ro 10RC and RB 10re turn it on. impedance? D. None of the above C. higher input impedance. A. Fixed-bias D. higher voltage gain. B. Common-base 32. The ________ configuration is C. Emitter-follower frequently used for impedance 19. What is the typical range of the matching. D. Voltage-divider? output impedance of a common-emitter A. fixed-bias configuration? 26. Which of the following represent(s) B. voltage-divider bias A. 10 to 100 the advantage(s) of the system C. emitter-follower B. 1 k to 5 k approach over the r-model approach? D. collector feedback C. 40 k to 50 k A. Thevenin's theorem can be D. 500 k to 1 k used. 33. Refer to this figure. You notice while B. The effect of changing the load servicing this amplifier that the output 20. What is the unit of the parameter ho? signal at Vout is reduced from normal. can be determined by a A. Volt The problem could be caused by simple equation. B. Ohm C. There is no need to go back to C. Siemen the ac equivalent D. No unit model and analyze the entire 21. Refer to this figure. Calculate the network. value of Rin(tot). 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. A. an open C3. D. one input and two outputs. B. an open C2. 28. The emitter-follower configuration C. an open base-emitter of Q2. has a ________ impedance at the input D. a shorted C2. and a ________ impedance at the 34. When the bypass capacitor is A. 37.7 k output. B. 3.77 k removed from a common-emitter A. low, low C. 378 amplifier, the voltage gain B. low, high A. increases. D. 2.25 k C. high, low B. decreases. 22. What is the range of the current gain D. high, high C. has very little effect. for BJT transistor amplifiers? 29. The differential amplifier produces 35. Refer to this figure. Determine the A. less than 1 outputs that are value of VC. B. 1 to 100 A. common mode. C. above 100 B. in-phase with the input D. All of the above voltages. 23. What does the negative sign in the C. the sum of the two input voltage gain of the common-emitter voltages. fixed-bias configuration indicate?  INDIABIX 1 46. In an un-bypassed emitter bias configuration hie replaces ________ in the re model. A. re B. C. re D. Ib 47. Which of the following is (are) true regarding the input impedance for A. 20 V A. 416 frequencies in the midrange 100 kHz of a B. 10 V B. 5k BJT transistor amplifier? C. 5V C. A. The input impedance is purely D. 0V D. 500 resistive. 41. Under which of the following B. It varies from a few ohms to 36. In a common-base amplifier, the conditions is the output impedance of megohms. input signal is connected to the the network approximately equal to RC C. An ohmmeter cannot be used A. base. for a common-emitter fixed-bias to measure the small- B. collector. configuration? signal ac input impedance. C. emitter. A. ro 10RC D. All of the above D. output. B. ro < 10RC 48. For the collector dc feedback 37. Which of the following is (are) true to C. r o < ro configuration, there is a ________ phase achieve a good overall voltage gain for D. r o > ro shift between the input and output the circuit? 42. Which of the following gains is less signals. A. The effect of Rs and RL must be than 1 for a common-base A. 0º considered as a product. configuration? B. 45º B. The effect of Rs and RL must A. Ai C. 90º be considered as a B. Av D. 180º product and evaluated individually. C. Ap 49. A common-collector amplifier has C. The effect of Rs and RL must be D. None of the above ________ input resistance, ________ evaluated individually. 43. Which of the following define(s) the current gain, and ________ voltage gain. D. None of the above conversion efficiency? A. high, high, low A. Ac power to the load/ac input B. high, low, low 38. To analyze the common-emitter power C. high, low, high amplifier, what must be done to determine the dc equivalent circuit? B. Ac power to the load/dc power 50. The total gain of a multistage A. leave circuit unchanged supplied amplifier is the ________. B. replace coupling and bypass C. Dc output power/ac input A. sum of individual voltage gains capacitors with opens power B. sum of dB voltage gains C. replace coupling and bypass D. All of the above 51. Which of the following capacitors with shorts 44. The dc emitter current of a transistor configurations has an output impedance D. replace VCC with ground is 8 mA. What is the value of r e? Zo equal to RC? 39. For the common-emitter amplifier ac A. 320 A. Fixed-bias common-emitter equivalent circuit, all capacitors are B. 13.3 k B. Common-emitter voltage- A. effectively shorts. C. divider with bypass B. effectively open circuits. D. 5.75 capacitor C. not connected to ground. 45. Which of the following should be C. Common-emitter voltage- D. connected to ground. done to obtain the ac equivalent of a divider without bypass network? capacitor 40. Refer to this figure. If an emitter A. Set all dc sources to zero D. All of the above bypass capacitor was installed, determine the value of Rin(base). B. Replace all capacitors by a 52. Refer to this figure. Find the value of short-circuit equivalent. Rin(base). C. Remove all elements bypassed by the short-circuit equivalent. D. All of the above  INDIABIX 1 58. Which of the following is (are) true 64. The input impedance of a BJT regarding the output impedance for amplifier is purely ________ in nature frequencies in the midrange 100 kHz of a and can vary from a few ________ to BJT transistor amplifier? ________. A. The output impedance is purely A. resistive, ohms, megohms resistive. B. capacitive, microfarads, farads B. It varies from a few ohms to C. inductive, millihenrys, henrys more than 2 M. D. None of the above C. An ohmmeter cannot be used 65. The ________ the source resistance to measure the small- A. 420 and/or ________ the load resistance, the signal ac output impedance. B. 50 k less the overall gain of an amplifier. D. All of the above A. smaller, smaller C. 940 59. Refer to this figure. The output signal B. smaller, larger D. 100.8 from the first stage of this amplifier is 0 C. larger, smaller 53. For a common-emitter amplifier, the V. The trouble could be caused by D. larger, larger purpose of the emitter bypass capacitor 66. Refer to this figure. If an emitter is bypass capacitor was installed, what A. no purpose, since it is shorted would the new Av be? 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. an open C4. A. voltage B. an open C2. B. current C. an open base-emitter of Q1. C. impedance D. a shorted C4. A. 4.96 D. All of the above 60. What is the limit of the efficiency B. 125 55. The loaded voltage gain of an defined by = Po / Pi? C. 398 amplifier is always more than the no- A. Greater than 1 D. 600 load level. B. Less than 1 67. A Darlington pair provides beta A. True C. Always 1 ________ for ________ input resistance. B. False D. None of the above A. multiplication, decreased 56. Which of the following 61. What is re equal to in terms of h B. multiplication, increased configurations has a voltage gain of RC parameters? C. division, decreased /re? A. hre / hoe 68. A Darlington pair amplifier has A. Fixed-bias common-emitter B. (hre + 1) / hoe A. high input impedance and high B. Common-emitter voltage- C. hie (hre / hoe)(1 + hfe) voltage gain. divider with bypass D. hfe B. low input impedance and low capacitor E. none of the above voltage gain. C. Fixed-bias common-emitter 62. What is the controlling current in a C. a voltage gain of about 1 and a and voltage-divider with common-base configuration? low input impedance. bypass capacitor A. Ie D. a low voltage gain and a high D. Common-emitter voltage- B. Ic input impedance. divider without bypass C. Ib capacitor D. None of the above 57. An emitter-follower amplifier has an FET DEVICES 63. Which of the following techniques input impedance of 107 k. The input can be used in the sinusoidal ac analysis signal is 12 mV. The approximate output of transistor networks? 1. Which of the following ratings voltage is (common-collector) A. Small-signal appear(s) in the specification sheet for A. 8.92 V B. Large-signal an FET? B. 112 mV C. Small- or large-signal A. Voltages between specific C. 12 mV D. None of the above terminals D. 8.9 mV B. Current levels  INDIABIX 1 C. Power dissipation A. 0.25 14. The drain current will always be one- D. All of the above B. 0.5 fourth of IDSS as long as the gate-to- C. 1 source voltage is ________ the pinch-off 2. What is the level of drain D. 0 value. current ID for gate-to-source voltages A. one-fourth VGS less than (more negative than) the 9. Referring to this transfer curve, B. one-half pinch-off level? determine ID at VGS = 2 V. C. three-fourths A. zero amperes D. None of the above B. IDSS C. Negative value 15. The transfer curve is not defined by D. Undefined Shockley's equation for the ________. A. JFET 3. What is the level of IG in an FET? B. depletion-type MOSFET A. Zero amperes C. enhancement-type MOSFET B. Equal to ID D. BJT C. Depends on VDS A. 0.444 mA D. Undefined 16. What is the purpose of adding two B. 1.333 mA Zener diodes to the MOSFET in this 4. What is the range of an FET's C. 0.111 mA figure? input impedance? D. 4.444 mA A. 10 to 1 k 10. Which of the following controls the B. 1 k to 10 k level of ID? C. 50 k to 100 k A. VGS D. 1 M to several hundred M B. VDS 5. Which of the following applies to a C. IG safe MOSFET handling? D. VDG A. Always pick up the transistor by 11. It is the insulating layer of ________ the casing. in the MOSFET construction that A. To reduce the input impedance B. Power should always be off accounts for the very desirable high B. To protect the MOSFET for when network changes are made. input impedance of the device. both polarities C. Always touch ground before A. SiO C. To increase the input handling the device. B. GaAs impedance D. All of the above C. SiO2 D. None of the above 6. Refer to this portion of a specification D. HCl 17. Referring to the following transfer sheet. Determine the values of reverse- 12. The BJT is a ________ device. The curve, determine the level of VGS when gate-source voltage and gate current if FET is a ________ device. the drain current is 20 mA. the FET was forced to accept it. 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. 25 Vdc, 200 nAdc B. 25 Vdc, 10 mAdc C. 6 Vdc, 1.0 nAdc A. 1.66 V D. None of the above B. 1.66 V 7. At which of the following condition(s) C. 0.66 V is the depletion region uniform? D. 0.66 V A. No bias 18. The region to the left of the pinch-off B. VDS > 0 V locus is referred to as the ________ C. VDS = VP A. 2.54 V region. D. None of the above B. 2.54 V A. saturation 8. What is the ratio of ID / IDSS for C. 12 V B. cutoff VGS = 0.5 VP? D. Undefined  INDIABIX 1 C. ohmic A. 2 A. Reduced channel resistance D. All of the above B. 3 B. Higher current and power C. 4 ratings 19. Refer to the following curves. D. 3 or 4 C. Faster switching time Calculate ID at VGS = 1 V. D. All of the above 25. Refer to the following figure. Calculate VGS at ID = 8 mA for k = 0.278 × 32. Hand-held instruments are available 2 2 10 A/V. to measure ________ for the BJT. A. DC B. IDSS C. VP D. All of the above 33. Which of the following input impedances is not valid for a JFET? 10 A. 10 9 A. 3.70 V B. 10 8 B. 5.36 V C. 10 11 C. 7.36 V D. 10 D. 2.36 V 34. Refer to the following characteristic 26. The level of VGS that results in ID = 0 curve. Calculate the resistance of the mA is defined by VGS = ________. FET at VGS = 0.25 V if ro = 10 k. A. 8.167 mA A. VGS(off) B. 4.167 mA B. VP C. 6.167 mA C. VDS D. 0.616 mA D. None of the above 20. Which of the following transistor(s) 27. Which of the following FETs has the has (have) depletion and enhancement lowest input impedance? types? A. JFET A. BJT B. MOSFET depletion-type C. MOSFET enhancement-type A. 1.1378 k B. JFET D. None of the above B. 113.78 C. MOSFET D. None of the above C. 11.378 28. Which of the following applies D. 11.378 k 21. The three terminals of the JFET are to MOSFETs? the ________, ________, and ________. A. No direct electrical connection 35. Which of the following is (are) A. gate, collector, emitter between the gate not an FET? B. base, collector, emitter terminal and the channel A. n-channel C. gate, drain, source B. Desirable high input impedance B. p-channel D. gate, drain, emitter C. Uses metal for the gate, drain, C. p-n channel and source connections D. n-channel and p-channel 22. Which of the following is (are) the D. All of the above terminal(s) of a field-effect transistor (FET). 29. At which of the following is the level FET AMPLIFIERS A. Drain of VDS equal to the pinch-off voltage? B. Gate A. When ID becomes equal to IDSS 1. A common-gate amplifier is similar in C. Source B. When VGS is zero volts configuration to which BJT amplifier? D. All of the above C. IG is zero A. common-emitter D. All of the above 23. A BJT is a ________-controlled B. common-collector device. The JFET is a ________ - 30. Which of the following represent(s) C. common-base controlled device. the cutoff region for an FET? D. emitter-follower A. voltage, voltage A. ID = 0 mA 2. The theoretical efficiency of a class D B. voltage, current B. VGS = VP amplifier is C. current, voltage C. IG = 0 A. 75%. D. current, current D. All of the above B. 85%. 24. How many terminals can a MOSFET 31. Which of the following is (are) the C. 90%. have? advantage(s) of VMOS over MOSFETs? D. 100%.  INDIABIX 1 3. A common-source amplifier is similar A. common-emitter in configuration to which BJT amplifier? B. common-collector A. common-base C. common-base B. common-collector D. common-gate C. common-emitter 9. Referring to this figure, calculate Av D. emitter-follower for yos = 58µS. 4. Refer to this figure. If R6 opened, the signal at the drain of Q1 would A. 176 mV p-p B. 88 mV p-p C. 48 mV p-p D. 24 mV p-p 14. Referring to the following figure, A. increase. calculate gm for VGSQ = 1.25 V. B. decrease. A. 7.29 C. remain the same. B. 7.50 D. distort. C. 8.05 D. 8.55 5. Refer to this figure. Find the value of VD. 10. Refer to this figure. If Vin = 1 V p-p, the output voltage Vout would be 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 A. 20 V VGSQ = ¼Vp. B. 11 V A. undistorted. C. 10 V B. clipped on the negative peaks. D. 9V C. clipped on the positive peaks. D. 0 Vp-p 6. A BJT is a ________-controlled device. 11. Use the following equation to A. current B. voltage calculate gm for a JFET having IDSS = 10 mA, VP = 5 V, and VGSQ = 2.5 V. 7. Referring to this figure, calculate Av if rd A. B. C. A. 2 mS D. B. 3 mS C. 4 mS 16. Where do you get the level of gm and D. 5 mS rd for an FET transistor? A. from the dc biasing 12. For what value of ID is gm equal to 0.5 arrangement gm0? A. 2.85 B. from the specification sheet A. 0 mA B. 3.26 C. from the characteristics B. 0.25 IDSS C. 2.95 D. All of the above C. 0.5 IDSS D. 3.21 D. IDSS 17. The class D amplifier uses what type 8. A common-drain amplifier is similar in of transistors? 13. Refer to this figure. If Vin = 20 mV p-p configuration to which BJT amplifier? A. JFETs what is the output voltage?  INDIABIX 1 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 A. C. to create a short-circuit B. C. A. 2 mS equivalent for ac analysis D. B. 3 mS D. All of the above C. 4 mS 19. An FET is a ________-controlled 24. Which of the following is a required D. 5 mS device. condition to simplify the equations for Zo and Av for the self-bias configuration? 31. Which type of FETs can operate with A. current A. rd a gate-to-source Q-point value of 0 V? B. voltage D B. rd = RD A. JFET 20. What is the input resistance C. rd D B. E-MOSFET (Rin(source)) of a common-gate amplifier? D. None of the above C. D-MOSFET A. Rs 25. The steeper the slope of the ID versus 32. On which of the following B. (1+ gm) || Rs VGS curve, the ________ the level of gm. parameters does rd have no or little C. 1 / gm A. less impact in a source-follower D. none of the above B. same configuration? 21. There is a ________º phase inversion C. greater A. Zi between gate and source in a source B. Zo follower. 26. What is the typical value for the C. Av A. 0 input impedance Zi for JFETs? @ D. All of the above B. 90 A. 100 k B. 1M 33. Refer to this figure. For midpoint C. 180 C. 10 M biasing, ID would be D. none of the above D. 1000 M 22. Refer to this figure. If C4 opened, the signal voltage at the drain of Q1 would 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 A. 10 mA. A. increase. B. one-half B. 7.5 mA. B. decrease. C. three-fourths C. 5 mA. C. remain the same. D. 2.5 mA. D. distort. 29. MOSFET digital switching is used to produce which digital gates? 34. Class D amplifiers differ from all 23. Referring to this figure, find Zo if yos = A. inverters other classes of amplifiers because 20µS. B. NOR gates A. the output transistors are C. NAND gates operated as switches. D. all of the above B. of their very low input capacitance. 30. Referring to the transfer C. of their high-frequency characteristics shown below, calculate response capabilities. gm at VGSQ = 1 V. D. they employ dual MOSFETs  INDIABIX 1 35. Refer to this figure. If R7 were to A. decrease in value, Vout would B. C. D. 40. Referring to this figure, calculate Zo if rd A. B. A. increase. C. B. decrease. D. C. remain the same. 45. The more horizontal the D. distort characteristic curves on the drain 36. Refer to this figure. If ID = 4 mA, find characteristics, the ________ the output A. impedance. the value of VGS. B. A. less C. B. same D. C. greater 41. Referring to this figure, calculate Zi if 46. Refer to this figure. If gm = 4000 mS rd and a signal of 75 mVrms is applied to the gate, calculate the p-p output voltage. A. 10.8 V B. 6V C. 0.7 V D. 6V A. 37. Which FET amplifier(s) has (have) a B. phase inversion between input and C. A. 990 mV output signals? D. B. 1.13 V p-p A. common-gate C. 2.8 V p-p B. common-drain 42. For the fixed-bias configuration, if r D D. 990 V p-p C. common-source < 10 RD , then Zo = ________. D. all of the above A. RD 47. Refer to this figure. The approximate B. RD || rD value of Rin is 38. What common factor determines the voltage gain and input resistance of a C. RG common-gate amplifier? D. -gm · (RD || rD ) A. RD 43. Referring to this figure, obtain gm for B. RL ID = 6 mA. C. gm 39. Referring to the figure below, determine the output impedance for VGS = 3 V at VDS = 5 V. A. B. 1.5 k. C. 3.3 k. A. 2.83 mS B. 3.00 mS D. 48 M. C. 3.25 mS 48. Which of the following is (are) D. 3.46 mS related to depletion-type MOSFETs? 44. Referring to this figure, calculate Z o A. VGSQ can be negative, zero, or for VGSQ = 3.2 V. positive.  INDIABIX 1 B. gm can be greater or smaller B. high input imped