4. Forward bias of a silicon P-N junction will produce a barrier voltage of approximately how many volts? A. 0.2 B. 0.3 C. 0.7 D. 0.

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1 1. The dc current through each diode in a bridge rectifier equals A. the load current B. half the dc load current C. twice the dc load current D. one-fourth the dc load current 2. When matching polarity connections are made and the potential difference (PD) is above 0.7 V, the diode is considered to be A. not working B. forward biased C. reverse biased D. an open switch 3. What is the current through the LED? A. 0 ma B. 23 ma C. 18 ma D. 13 ma 4. Forward bias of a silicon P-N junction will produce a barrier voltage of approximately how many volts? A. 0.2 B. 0.3 C. 0.7 D A P-N junction mimics a closed switch when it: A. has a low junction resistance B. is reverse biased C. cannot overcome its barrier voltage D. has a wide depletion region 6. 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 7. Determine the value of when = 100. A B. 101 C D. Cannot be solved with the information provided 1

2 8. dc =. A. I B / I E B. I C / I E C. I C / I B 9. Which component of the collector current I C is called the leakage current? A. Majority B. Independent C. Minority 10. The current gain for the Darlington connection is.. A. B. C. D. 11. A common-emitter amplifier has voltage gain, current gain,. power gain, and input impedance. A. high, low, high, low B. high, high, high, low C. high, high, high, high D. low, low, low, high 12. The configuration is frequently used for impedance matching. A. fixed-bias B. voltage-divider bias C. emitter-follower D. collector feedback 13. A transistor has a of 250 and a base current, I B, of 20 A. The collector current, I C, equals: A. 500 A B. 5 ma C. 50 ma D. 5 A 14. If a transistor operates at the middle of the dc load line, a decrease in the current gain will move the Q point: A. off the load line B. nowhere C. up D. down 2

3 15. Which of the following materials is used in light emitting diodes? A. Ge B. Si C. GaAs D. W 16. A 15 V source is connected across a 12 resistor. How much energy is used in three minutes? A. 938 Wh B Wh C Wh D. 5.6 Wh 17.How much continuous current can be drawn from a 60 Ah battery for 14 h? A A B. 428 A C A D. 4.2 A 18. In a series RLC circuit that is operating above the resonant frequency, the current A. lags the applied voltage B. leads the applied voltage C. is in phase with the applied voltage D. is zero 19. A resonant circuit has a lower critical frequency of 7 khz and an upper critical frequency of 13 khz. The bandwidth of the circuit is A. 7 khz B. 13 khz C. 20 khz 20. What is the ratio of the secondary voltage to the primary voltage with the turn ratio in the windings? A. N 2/N 1 B. (N 1/N 2) 2 C. (N 1/N 2) 1/3 D. N 1 N The principal advantage(s) of MOSFETs over BJTs is (are) A. their biasing networks are simpler. B. their drive requirements are simpler. C. they can be connected in parallel for added drive capability. D. all of the above 22. The feedback signal in a(n) oscillator is derived from a capacitive voltage divider in the LC circuit. A. Hartley B. Armstrong C. Colpitts D. Phase Shift 3

4 23. Determine the output frequency for a frequency division circuit that contains 12 flip-flops with an input clock frequency of MHz. A khz B. 5 khz C khz D. 15 khz 24. Propagation delay time, t PLH, is measured from the A. triggering edge of the clock pulse to the LOW-to-HIGH transition of the output B. triggering edge of the clock pulse to the HIGH-to-LOW transition of the output C. preset input to the LOW-to-HIGH transition of the output D. clear input to the HIGH-to-LOW transition of the output 25. How many flip-flops are in the 7493 IC? A. 1 B. 2 C. 4 D Which of the following describes the operation of a positive edge-triggered D flip-flop? A. If both inputs are HIGH, the output will toggle. B. The output will follow the input on the leading edge of the clock. C. When both inputs are LOW, an invalid state exists. D. The input is toggled into the flip-flop on the leading edge of the clock and is passed to the output on the trailing edge of the clock. 27. A MOD-16 ripple counter is holding the count What will the count be after 31 clock pulses? A B C D A MOD-12 and a MOD-10 counter are cascaded. Determine the output frequency if the input clock frequency is 60 MHz. A. 500 khzb. 1,500 khz C. 6 MHz D.5 MHz 29. Which segments of a seven-segment display would be required to be active to display the decimal digit 2? A. a, b, d, e, and g B. a, b, c, d, and g C. a, c, d, f, and g D. a, b, c, d, e, and f 30. The terminal count of a typical modulus-10 binary counter is. A B C D One of the major drawbacks to the use of asynchronous counters is: A. low-frequency applications are limited because of internal propagation delays B. high-frequency applications are limited because of internal propagation delays C. asynchronous counters do not have major drawbacks and are suitable for use in high- and lowfrequency counting applications D. asynchronous counters do not have propagation delays and this limits their use in high-frequency applications 4

5 32. Which of the following flip-flops experience race around condition? A. J-K B. R-S C. Both J-K and R-S D. Neither J-K nor R-S 33. The hexadecimal equivalent of 15,536 is A. 3CB0 B. 3C66 C. 63C0 D Synchronous (parallel) counters eliminate the delay problems encountered with asynchronous (ripple) counters because the: A. input clock pulses are applied only to the first and last stages. B. input clock pulses are applied only to the last stage. C. input clock pulses are applied simultaneously to each stage. D. input clock pulses are not used to activate any of the counter stages 35. What is the ratio of I D / I DSS for V GS = 0.5 V P? A B. 0.5 C. 1 D The drain current will always be one-fourth of I DSS as long as the gate-to-source voltage is the pinch-off value. A. one-fourth B. one-half C. three-fourths 37. The bandwidth of narrow band FM signal is approximately equal to A. f m B. 2f m C. 2β(f m + 1) 38. A 12 ma current source has an internal resistance, R S, of 1.2 k. The equivalent voltage source is A. 144 V B V C. 7.2 V D. 72 mv 39. The parallel combination of a 470 resistor and a 1.2 k resistor is in series with the parallel combination of three 3 k resistors. A 200 V source is connected across the circuit. The resistor with the most current has a value of A. 470 or 1.2 k B. 3 k C. 470 D. 1.2 k 5

6 40. In a certain five-step R/2R ladder network, the smallest resistor value is 1 k. The largest value is A. indeterminable B. 2 k C. 10 k D. 20 k 41. Select one of the following statements that best describes the parity method of error detection: A. Parity checking is best suited for detecting single-bit errors in transmitted codes. B. Parity checking is best suited for detecting double-bit errors that occur during the transmission of codes from one location to another. C. Parity checking is not suitable for detecting single-bit errors in transmitted codes. D. Parity checking is capable of detecting and correcting errors in transmitted codes. 42. In a Y-Y source/load configuration, the A. phase current, the line current, and the load current are all equal in each phase B. phase current, the line current, and the load current are 120 out of phase C. phase current and the line current are in phase, and both are 120 out of phase with the load current D. line current and the load current are in phase, and both are out of phase with the phase current 43. The bandwidth of standard AM signal (AM-DSBFC) is given by A. f m B. 2f m C. depending upon modulation index D. All of the above 44. If the radio receiver is tuned at 855 khz and the intermediate frequency is 455 kh, then the local oscillator frequency should be A. 455 khz B khz C khz D khz 45. If voltage across a resistance doubles A. the current is halved B. the resistance doubles C. the current is unchanged D. none of the above 46. A 50 kw carrier is to be modulated to a level of 80 %. The total side band power is equal to A. 67kW B. 16kW C. 32kW 47. For audio systems, the reference level is generally accepted as. A. 1 mw B. 1 W C. 10 mw D. 100 mw 6

48. Determine the peak value of the output waveform. A. 25 V B. 15 V C. 25 V D. 15 V 49. Determine the voltage across the resistor. A. 0 V B. 0.09 V C. 0.2 V D. 0.44 V 50.

7 48. Determine the peak value of the output waveform. A. 25 V B. 15 V C. 25 V D. 15 V 49. Determine the voltage across the resistor. A. 0 V B V C. 0.2 V D V 50. 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 51. The intrinsic stand off ratio of a UJT is given by A. R B1 + R B2 B. (R B1 + R B2)/R B1 C. R B1/( R B1 + R B2) D. (R B1 + R B2)/R B2 52. Between the peak point and the Valley point of UJT emitter characteristics we have the following region A. Saturation B. Negative resistance C. Cut-off 53. The V-I characteristics of a triac are essentially identical to those of A. Transistor in 2nd quadrant B. UJT in Ist quadrant 7

8 C. SCR in Ist quadrant 54. The drain current I D in a JFET is given by A. I D = I DSS[1-V GS/V P] 2 B. I D = I DSS[1+V GS/V P] 2 C.I D = I DSS[1- V P/V GS] 2 D. I D = I DSS[1+V GS/V P] 1/2 55. Which of the following devices has the highst input impedance A. MOSFET B. JFET C. BJT D. Crystal diode 56. If the input impedance of an amplifier without feedback is Z in, the impedance with negative feedback will be A. Z in/(1 + A vm v) B. Z in(1 + A vm v) C. (1 + A vm v)/z in D. Z in(1 - A vm v) 57. Thevenin s theorem replaces the complicated circuit facing a load by an A. ideal voltage source and parallel resistor B. ideal current source and parallel resistor C. ideal current source and series resistor D. ideal voltage source and series resistor 58. Efficiency at maximum power transfer is A. 50% B. 25% C. 100% D. 75% 59. In an AM wave, useful power is carried by A. carrier B. Sidebands C. both carrier and sidebands 60. The Carsons rule for the calculation of bandwidth of FM signal is given by A. 2f m(β + 1) B. 2β(f m + 1) C. 2 f(1 + f m) D. 2f m( f + 1) 8

OBJECTIVE TYPE QUESTIONS

OBJECTIVE TYPE QUESTIONS Q.1 The breakdown mechanism in a lightly doped p-n junction under reverse biased condition is called (A) avalanche breakdown. (B) zener breakdown. (C) breakdown by tunnelling.