MCQOPTIONS
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MCQOPTIONS
This section includes 1017 Mcqs, each offering curated multiple-choice questions to sharpen your Electronics & Communication Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Comparatively, power amplifier has β. |
| A. | large |
| B. | very large |
| C. | small |
| D. | very small |
| Answer» D. very small | |
| 2. |
A coupling capacitor is |
| A. | a dc short |
| B. | an ac open |
| C. | a dc open and an ac short |
| D. | a dc short and an ac open |
| Answer» D. a dc short and an ac open | |
| 3. |
A power amplifier is limited to use at one fixed frequency. |
| A. | class a |
| B. | class b or ab |
| C. | class c |
| D. | class d |
| Answer» D. class d | |
| 4. |
Between the branch voltages of a loop the Kirchhoff s voltage law imposes |
| A. | non-linear constraints |
| B. | linear constraints |
| C. | no constraints |
| D. | none of the above |
| Answer» C. no constraints | |
| 5. |
A class A power amplifier uses transistor(s). |
| A. | two |
| B. | one |
| C. | three |
| D. | four |
| Answer» C. three | |
| 6. |
An amplifier without feedback has a voltage gain of 50, input resistance is 1 KΩ & Output resistance of 2.5KΩ.The input resistance of the current-shunt negative feedback amplifier using the above amplifier with a feedback factor of 0.2 is |
| A. | 1/11kΩ |
| B. | 1/5kΩ |
| C. | 5kΩ |
| D. | 11kΩ |
| Answer» C. 5kΩ | |
| 7. |
The reflected impedance seen from one side of the transformer to the other side is . |
| A. | n1/n2 |
| B. | (n1/n2)2 |
| C. | (n1/n2)1/3 |
| D. | n1× n2 |
| Answer» C. (n1/n2)1/3 | |
| 8. |
A class A amplifier dissipates power when the load is drawing maximum power from the circuit. |
| A. | the least |
| B. | about the same |
| C. | the most |
| D. | none of the above |
| Answer» B. about the same | |
| 9. |
The barrier potential across each silicon depletion layer is |
| A. | 0v |
| B. | 0.3v |
| C. | 0.7v |
| D. | 1v |
| Answer» D. 1v | |
| 10. |
Kirchhoff's voltage law is related to |
| A. | junction currents |
| B. | battery emfs |
| C. | ir drops |
| D. | both b & c |
| Answer» E. | |
| 11. |
The concept on which superposition theorem is based on |
| A. | reciprocity |
| B. | duality |
| C. | non-linearity |
| D. | linearity |
| Answer» E. | |
| 12. |
The difference between VOH and VIH voltages is known as |
| A. | input margin. |
| B. | noise margin. |
| C. | output differential. |
| D. | input level. |
| Answer» C. output differential. | |
| 13. |
The ac base voltage of an emitter follower is across the |
| A. | emitter diode |
| B. | dc emitter resistor |
| C. | load resistor |
| D. | emitter diode and external ac emitter resistance |
| Answer» E. | |
| 14. |
In an npn transistor, the majority carriers in the emitter are |
| A. | free electrons |
| B. | holes |
| C. | neither |
| D. | both |
| Answer» B. holes | |
| 15. |
Power amplifiers generally use transformer coupling because transformer coupling provides |
| A. | cooling of the circuit |
| B. | distortionless output |
| C. | impedance matching |
| D. | good frequency response |
| Answer» D. good frequency response | |
| 16. |
The total decibel voltage gain of two cascaded voltage amplifier where individual voltage gains are 10 and 100 is |
| A. | 20 |
| B. | 60 |
| C. | 800 |
| D. | 1000 |
| Answer» C. 800 | |
| 17. |
Unused inputs on TTL, AND, and NAND gates |
| A. | degrade the gate\s noise immunity. |
| B. | if left open will have the same effect as high inputs. |
| C. | should be tied high. |
| D. | all of the above are correct. |
| Answer» E. | |
| 18. |
In a class A transformer-coupled amplifier, the the value of VCEmax and the the value of VCEmin, the the efficiency to (from) the theoretical limit of 50%. |
| A. | larger, smaller, farther |
| B. | larger, smaller, closer |
| C. | smaller, larger, closer |
| D. | none of the above |
| Answer» C. smaller, larger, closer | |
| 19. |
If the operating point changes, the h-parameters of transistor |
| A. | also change |
| B. | do not change |
| C. | may or may not change |
| D. | none of above |
| Answer» B. do not change | |
| 20. |
Calculate the effective resistance seen looking into the primary of a 20:1 transformer connected to an 8- Ω load. |
| A. | 3.2 kΩ |
| B. | 3.0 kΩ |
| C. | 2.8 kΩ |
| D. | 1.8 kΩ |
| Answer» B. 3.0 kΩ | |
| 21. |
A class amplifier is biased slightly above cutoff and operates in the linear region for slightly more than 180º of the input cycle. |
| A. | a |
| B. | b |
| C. | c |
| D. | ab |
| Answer» E. | |
| 22. |
While calculating Rth in Thevenin's theorem and Norton equivalent |
| A. | all independent sources are made dead |
| B. | only current sources are made dead |
| C. | only voltage sources are made dead |
| D. | all voltage and current sources are made dead |
| Answer» B. only current sources are made dead | |
| 23. |
The maximum efficiency of a transformer-coupled class A amplifier is . |
| A. | 25% |
| B. | 50% |
| C. | 78.5% |
| D. | 63.6% |
| Answer» C. 78.5% | |
| 24. |
What transformer turns ratio is required to match an 8-speaker load so that the effective load resistance seen at the primary is 12.8 k? |
| A. | 20:01 |
| B. | 40:01:00 |
| C. | 50:01:00 |
| D. | 60:01:00 |
| Answer» C. 50:01:00 | |
| 25. |
The major advantage of TTL logic circuits over CMOS is |
| A. | lower propagation delay. |
| B. | the ability to output higher voltages. |
| C. | more modern design. |
| D. | very low power consumption |
| Answer» B. the ability to output higher voltages. | |
| 26. |
The output transformer used in a power amplifier is a transformer. |
| A. | 1:1 ratio |
| B. | step-up |
| C. | step-down |
| D. | none of the above |
| Answer» D. none of the above | |
| 27. |
Typical TTL HIGH level output voltage is |
| A. | 0.3 v. |
| B. | 5.0 v. |
| C. | 3.4 v. |
| D. | 4.8 v. |
| Answer» D. 4.8 v. | |
| 28. |
The upper transistor of a totem-pole output is OFF when the gate output is |
| A. | logic 1. |
| B. | malfunctioning. |
| C. | high. |
| D. | low. |
| Answer» E. | |
| 29. |
For audio systems, the reference level is generally accepted as . |
| A. | 1 mw |
| B. | 1 w |
| C. | 10 mw |
| D. | 100 mw |
| Answer» B. 1 w | |
| 30. |
In order to interface an FPGA with an external device, you must set the value of the |
| A. | sink current. |
| B. | external power supply. |
| C. | source current. |
| D. | all of the above |
| Answer» E. | |
| 31. |
The algebraic sum of in a network of conductors meeting at a point is zero. |
| A. | voltages |
| B. | currents |
| C. | resistances |
| D. | inductances |
| Answer» C. resistances | |
| 32. |
The greater the power handled by the power transistor, the |
| A. | the higher |
| B. | the lower |
| C. | there is no |
| D. | none of the above |
| Answer» B. the lower | |
| 33. |
A certain transistor has IC = 15 mA and IB = 167 µA; βDC is: |
| A. | 15 |
| B. | 167 |
| C. | 0.011 |
| D. | 90 |
| Answer» E. | |
| 34. |
A common emitter circuit is also called circuit. |
| A. | grounded emitter |
| B. | grounded collector |
| C. | grounded base |
| D. | emitter follower |
| Answer» B. grounded collector | |
| 35. |
The ratio output rms power in watts to the input dc power in watts in the different amplifier class is called . |
| A. | gain |
| B. | amplification factor |
| C. | efficiency |
| D. | phase power |
| Answer» D. phase power | |
| 36. |
The beta of a power transistor is generally . |
| A. | more than 200 |
| B. | 100 to 200 |
| C. | less than 100 |
| Answer» D. | |
| 37. |
The fundamental component is typically any harmonic component. |
| A. | larger than |
| B. | the same as |
| C. | smaller than |
| D. | none of the above |
| Answer» B. the same as | |
| 38. |
When negative current feedback is applied to an amplifier, its output impedance |
| A. | increases |
| B. | remains unchanged |
| C. | decreases |
| D. | becomes zero |
| Answer» B. remains unchanged | |
| 39. |
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. |
| Answer» E. | |
| 40. |
The output current for a LOW output is called a(n) |
| A. | exit current. |
| B. | sink current. |
| C. | ground current. |
| D. | fan-out. |
| Answer» C. ground current. | |
| 41. |
Bootstrapping is used in emitter follower configurations to |
| A. | stabilize the voltage gain against process variations |
| B. | increase current gain |
| C. | reduce the output resistance |
| D. | increase the input resistance |
| Answer» E. | |
| 42. |
The lower transistor of a totem-pole output is OFF when the gate output is |
| A. | high. |
| B. | malfunctioning. |
| C. | low. |
| D. | over driven. |
| Answer» B. malfunctioning. | |
| 43. |
The base of an npn transistor is thin and |
| A. | heavily doped |
| B. | lightly doped |
| C. | metallic |
| D. | doped by a pentavalent material |
| Answer» C. metallic | |
| 44. |
An open fuse circuit has a resistance equal to |
| A. | zero |
| B. | unity |
| C. | at least 100Ω atstandard |
| D. | infinity |
| Answer» E. | |
| 45. |
What is the most important characteristic of a common collector amplifier? |
| A. | high input voltage |
| B. | high input resistance |
| C. | high output resistance |
| D. | its being an amplifier circuit |
| Answer» C. high output resistance | |
| 46. |
Which of the following is the other name of the output stage in an amplifier? |
| A. | load stage |
| B. | audio stage |
| C. | power stage |
| D. | rf stage |
| Answer» D. rf stage | |
| 47. |
The Bode plot is applicable to |
| A. | all phase network |
| B. | minimum phase network |
| C. | maximum phase network |
| D. | lag lead network |
| Answer» C. maximum phase network | |
| 48. |
A BJT has an IB of 50 µA and a βDC of 75; IC is: |
| A. | 375 ma |
| B. | 37.5 ma |
| C. | 3.75 ma |
| D. | 0.375 ma |
| Answer» D. 0.375 ma | |
| 49. |
What is the effect of cascading amplifier stages? |
| A. | increase in the voltage gain and increase in the bandwidth |
| B. | increase in the voltage gain and reduction in the bandwidth |
| C. | decrease in the voltage gain and increase in the bandwidth |
| D. | increase in the voltage gain and reduction in the bandwidth |
| Answer» C. decrease in the voltage gain and increase in the bandwidth | |
| 50. |
Class D operation can achieve power efficiency of over . |
| A. | 90% |
| B. | 78.50% |
| C. | 50% |
| D. | 25% |
| Answer» B. 78.50% | |