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MCQOPTIONS
This section includes 1475 Mcqs, each offering curated multiple-choice questions to sharpen your Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 451. |
Calculate the efficiency of a transformer-coupled class A amplifier for a supply of 15 V and an output of V(p) = 10 V. |
| A. | 25% |
| B. | 33.3% |
| C. | 50% |
| D. | 78.5% |
| Answer» C. 50% | |
| 452. |
________ amplifiers primarily provide sufficient power to an output load to drive a speaker from a few watts to tens of watts. |
| A. | Small-signal |
| B. | Power |
| C. | None of the above |
| Answer» C. None of the above | |
| 453. |
You have an application for a power amplifier to operate on FM radio frequencies. The most likely choice would be a ________ amplifier. |
| A. | class A |
| B. | class B |
| C. | class C |
| D. | class AB |
| Answer» D. class AB | |
| 454. |
A class B amplifier operates in the linear region for |
| A. | slightly more than 180 of the input cycle. |
| B. | 360 of the input cycle. |
| C. | slightly less than 180 of the input cycle. |
| D. | much less than 180 of the input cycle. |
| Answer» D. much less than 180 of the input cycle. | |
| 455. |
A BJT has an IB of 50 A and a DC of 75; IC is: |
| A. | 375 mA |
| B. | 37.5 mA |
| C. | 3.75 mA |
| D. | 0.375 mA |
| Answer» D. 0.375 mA | |
| 456. |
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 |
| Answer» C. 1.2 V | |
| 457. |
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 |
| Answer» B. pnn and nnp | |
| 458. |
The term BJT is short for |
| A. | base junction transistor. |
| B. | binary junction transistor. |
| C. | both junction transistor. |
| D. | bipolar junction transistor. |
| Answer» E. | |
| 459. |
A certain transistor has IC = 15 mA and IB = 167 A; DC is: |
| A. | 15 |
| B. | 167 |
| C. | 0.011 |
| D. | 90 |
| Answer» E. | |
| 460. |
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 |
| Answer» D. none of the above | |
| 461. |
What is the minimum number of conversions per second of a clock rate of 1 MHz operating a 10-stage counter in an ADC? |
| A. | 1000 |
| B. | 976 |
| C. | 769 |
| D. | 697 |
| Answer» C. 769 | |
| 462. |
Which of the following is (are) the results of improvements built into a comparator IC? |
| A. | Faster switching between the two output levels |
| B. | Noise immunity |
| C. | Outputs capable of directly driving a variety of loads |
| D. | All of the above |
| Answer» E. | |
| 463. |
Calculate VB2. |
| A. | 0 V |
| B. | 0.7 V |
| C. | 9.3 V |
| D. | 10.7 V |
| Answer» D. 10.7 V | |
| 464. |
The main features of a large-signal amplifier is the circuit's ________. |
| A. | power efficiency |
| B. | maximum power limitations |
| C. | impedance matching to the output device |
| D. | All of the above |
| Answer» E. | |
| 465. |
The principal advantage(s) of BJTs over MOSFETs is (are) that |
| A. | voltage drop across the transistor is important. |
| B. | they are not as prone to ESD. |
| C. | both of the above |
| D. | none of the above |
| Answer» D. none of the above | |
| 466. |
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 |
| Answer» C. 1.065 mA | |
| 467. |
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 |
| Answer» C. 13.3 V | |
| 468. |
Switching regulator efficiencies can be greater than ________ percent. |
| A. | 60 |
| B. | 70 |
| C. | 80 |
| D. | 90 |
| Answer» E. | |
| 469. |
If a peak rectified voltage for the full-wave filter circuit is 40 V, calculate the filter dc voltage if C = 75 F and load current is 40 mA. |
| A. | 27.9 V |
| B. | 32.12 V |
| C. | 37.78 V |
| D. | 40 V |
| Answer» D. 40 V | |
| 470. |
In which period is the capacitor filter discharged through the load in a full-wave rectifier? |
| A. | The time during the positive cycle |
| B. | The time during which the diodes are not conducting |
| C. | The time during which the diode(s) is (are) conducting |
| D. | The time during the negative cycle |
| Answer» C. The time during which the diode(s) is (are) conducting | |
| 471. |
The 7805 regulator IC provides ________. |
| A. | 5 V |
| B. | 5 V |
| C. | 12 V |
| D. | 12 V |
| Answer» B. 5 V | |
| 472. |
What is the range of the voltage level of the LM317 adjusted voltage regulator? |
| A. | 0 V to 5 V |
| B. | 1.2 V to 37 V |
| C. | 5 V to 24 V |
| D. | 5 V to 24 V |
| Answer» C. 5 V to 24 V | |
| 473. |
A voltage regulator with a no-load output dc voltage of 12 V is connected to a load with a resistance of 10 . If the load resistance decreases to 7.5 , the load voltage will decrease to 10.9 V. The load current will be ________, and the percent load regulation is ________. |
| A. | 1.45 A, 90.8% |
| B. | 1.45 A, 10.09% |
| C. | 1.2 A, 90.8% |
| D. | 1.2 A, 10.09% |
| Answer» C. 1.2 A, 90.8% | |
| 474. |
Refer to the given figure. Determine the output voltage, VOUT. |
| A. | 25 V |
| B. | 5.1 V |
| C. | 20.2 V |
| D. | 4.1 V |
| Answer» D. 4.1 V | |
| 475. |
What is the typical dropout voltage for the 7812 fixed positive voltage regulator? |
| A. | 4 mV |
| B. | 100 mV |
| C. | 1.5 V |
| D. | 2 V |
| Answer» E. | |
| 476. |
Refer to the given figure. If the load is short-circuited, what would be the maximum current through R1? |
| A. | 1 A |
| B. | 1.2 A |
| C. | 1.5 A |
| D. | 5 A |
| Answer» D. 5 A | |
| 477. |
________ regulation can be defined as the percentage change in the output voltage for a given change in load current. |
| A. | Line |
| B. | Load |
| Answer» C. | |
| 478. |
The purpose of the added RC section is to pass most of the dc component while reducing as much of the ac component as possible. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 479. |
In a series regulator, what is the purpose of fold-back limiting? |
| A. | to provide more current in the case of a short circuit |
| B. | to limit output voltage if input voltage goes too high |
| C. | to bypass the pass-transistor, if the pass-transistor should fail |
| D. | to provide current up to a maximum, but drop current to a lower value when the output becomes shorted, to prevent overheating of the device |
| Answer» E. | |
| 480. |
Refer to the given figure. The purpose for the zener diode D1 is |
| A. | to supply a reference voltage. |
| B. | to amplify the error signal. |
| C. | to sense the error signal. |
| D. | to limit the input voltage to the circuit. |
| Answer» B. to amplify the error signal. | |
| 481. |
In a simple series regulator circuit, which of the following components is the controlling element? |
| A. | Load resistor |
| B. | Zener diode |
| C. | Transistor Q |
| D. | <sub>1</sub> |
| E. | None of the above |
| Answer» D. <sub>1</sub> | |
| 482. |
Refer to the given figure. This circuit is known as |
| A. | a series-pass voltage regulator. |
| B. | a shunt voltage regulator. |
| C. | a step-up switching regulator. |
| D. | a step-down switching regulator. |
| Answer» B. a shunt voltage regulator. | |
| 483. |
Negative feedback added to an op-amp ________ the bandwidth and ________ the gain. |
| A. | increases, increases |
| B. | increases, decreases |
| C. | decreases, decreases |
| D. | decreases, increases |
| Answer» C. decreases, decreases | |
| 484. |
When the loop is in lock in a PLL, the input frequency is ________ the output frequency from the VCO. |
| A. | the same as |
| B. | greater than |
| C. | smaller than |
| D. | None of the above |
| Answer» B. greater than | |
| 485. |
In a comparator, the reference voltage is connected to ________ input terminal and the input signal is applied to ________ input terminal. |
| A. | only the minus, only the plus |
| B. | only the plus, only the minus |
| C. | either the plus or minus, the other |
| D. | None of the above |
| Answer» D. None of the above | |
| 486. |
Zener diodes with breakdown voltages less than 5 V operate predominantly in what type of breakdown? |
| A. | avalanche |
| B. | zener |
| C. | varactor |
| D. | Schottky |
| Answer» C. varactor | |
| 487. |
Both junctions of a BJT should be forward-biased for linear operation. |
| A. | True |
| B. | False |
| Answer» C. | |
| 488. |
The 7812 regulator IC provides ________. |
| A. | 5 V |
| B. | 5 V |
| C. | 12 V |
| D. | 12 V |
| Answer» D. 12 V | |
| 489. |
Refer to the given figure. If the zener diode had a rating of 1.7 V, the output voltage would be |
| A. | 2.13 V. |
| B. | 8.36 V. |
| C. | 20.16 V. |
| D. | 25 V. |
| Answer» C. 20.16 V. | |
| 490. |
Refer to the given figure. This circuit operates at a ________ frequency, and its efficiency is ________. |
| A. | low, low |
| B. | low, high |
| C. | high, high |
| D. | high, low |
| Answer» D. high, low | |
| 491. |
Voltage regulators keep a constant ________ output voltage when the input or load varies within limits. |
| A. | dc |
| B. | ac |
| C. | ripple |
| Answer» B. ac | |
| 492. |
Calculate the value of C1 = C2 for the Wien bridge oscillator to operate at a frequency of 20 kHz. Assume R1 = R2 = 50 k and R3 = 3R4 = 600? |
| A. | 1.59 pF |
| B. | 15.9 pF |
| C. | 159 pF |
| D. | 1.59 nF |
| Answer» D. 1.59 nF | |
| 493. |
Only the condition A = ________ must be satisfied for self-sustained oscillations to result. |
| A. | 0 |
| B. | 1 |
| C. | 1 |
| D. | None of the above |
| Answer» D. None of the above | |
| 494. |
At what phase shift is the magnitude of A at its maximum in the Nyquist plot? |
| A. | 90 |
| B. | 180 |
| C. | 270 |
| D. | 0 |
| Answer» C. 270 | |
| 495. |
Calculate the ripple voltage of a full-wave rectifier with a 75-F filter capacitor connected to a load drawing 40 mA. |
| A. | 1.20 V |
| B. | 1.28 V |
| C. | 1.32 V |
| D. | 1.41 V |
| Answer» C. 1.32 V | |
| 496. |
An SCR acts to control the speed of an electric motor by ________ the ________ of the pulse delivered to the motor. |
| A. | varying, width |
| B. | increasing, amplitude |
| C. | decreasing, gate width |
| D. | none of these |
| Answer» B. increasing, amplitude | |
| 497. |
Which symbol represents a UJT? |
| A. | a |
| B. | b |
| C. | c |
| D. | d |
| E. | e |
| Answer» C. c | |
| 498. |
Which of the following devices might best be used to control an electric motor? |
| A. | an SCS |
| B. | a PUT |
| C. | an SCR |
| D. | a diac |
| Answer» D. a diac | |
| 499. |
What is the correct symbol for an SCR? |
| A. | a |
| B. | b |
| C. | c |
| D. | d |
| E. | e |
| Answer» B. b | |
| 500. |
You have a light-dimmer circuit using an SCR. In testing the circuit, you find that IG = 0 mA and the light is still on. You conclude that the trouble might be one of the following: |
| A. | the SCR is open. |
| B. | the switch is faulty. |
| C. | the gate circuit is shorted. |
| D. | this is normal; nothing is wrong. |
| Answer» E. | |