MCQOPTIONS
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MCQOPTIONS
This section includes 38 Mcqs, each offering curated multiple-choice questions to sharpen your Electronic Devices Circuits knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
The piezoelectric effect in a crystal is ___________ |
| A. | A voltage developed because of mechanical stress |
| B. | A change in resistance because of temperature |
| C. | A change in frequency because of temperature |
| D. | None of the above |
| Answer» B. A change in resistance because of temperature | |
| 2. |
In an LC oscillator, if the value of L is increased four times, the frequency of oscillations is ___________ |
| A. | Increased 2 times |
| B. | Decreased 4 times |
| C. | Increased 4 times |
| D. | Decreased 2 times |
| Answer» E. | |
| 3. |
A second condition for oscillations is ___________ |
| A. | A gain of 1 around the feedback loop |
| B. | No gain around the feedback loop |
| C. | The attention of the feedback circuit must be one-third |
| D. | The feedback circuit must be capacitive |
| Answer» B. No gain around the feedback loop | |
| 4. |
In an LC circuit, when the capacitor is maximum, the inductor energy is ___________ |
| A. | Minimum |
| B. | Maximum |
| C. | Half-way between maximum and minimum |
| D. | None of the above |
| Answer» B. Maximum | |
| 5. |
An important limitation of a crystal oscillator is ___________ |
| A. | Its low output |
| B. | Its high Q |
| C. | Less availability of quartz crystal |
| D. | Its high output |
| Answer» B. Its high Q | |
| 6. |
The application where one would most likely find a crystal oscillator is ___________ |
| A. | Radio receiver |
| B. | Radio transmitter |
| C. | AF sweep generator |
| D. | None of the above |
| Answer» C. AF sweep generator | |
| 7. |
___________ is a fixed frequency oscillator |
| A. | Phase-shift oscillator |
| B. | Hartely-oscillator |
| C. | Colpitt's oscillator |
| D. | Crystal oscillator |
| Answer» E. | |
| 8. |
In an LC transistor oscillator, the active device is ___________ |
| A. | LC tank circuit |
| B. | Biasing circuit |
| C. | Transistor |
| D. | None of the above |
| Answer» D. None of the above | |
| 9. |
In a Wien-bridge oscillator, if the resistances in the positive feedback circuit are decreased, the frequency ___________ |
| A. | Remains the same |
| B. | Decreases |
| C. | Increases |
| D. | Insufficient data |
| Answer» D. Insufficient data | |
| 10. |
If the crystal frequency changes with temperature, we say that crystal has ___________ temperature coefficient |
| A. | Positive |
| B. | Zero |
| C. | Negative |
| D. | None of the above |
| Answer» B. Zero | |
| 11. |
The Q of the crystal is of the order of ___________ |
| A. | 100 |
| B. | 1000 |
| C. | 50 |
| D. | More than 10,000 |
| Answer» E. | |
| 12. |
For an oscillator to properly start, the gain around the feedback loop must initially be |
| A. | 1 |
| B. | Greater than 1 |
| C. | Less than 1 |
| D. | Equal to attenuation of feedback circuit |
| Answer» C. Less than 1 | |
| 13. |
In Colpitt's oscillator, feedback is obtained ___________ |
| A. | By magnetic induction |
| B. | By a tickler coil |
| C. | From the centre of split capacitors |
| D. | None of the above |
| Answer» D. None of the above | |
| 14. |
In a phase shift oscillator, the frequency determining elements are ___________ |
| A. | L and C |
| B. | R, L and C |
| C. | R and C |
| D. | None of the above |
| Answer» D. None of the above | |
| 15. |
An oscillator converts ___________ |
| A. | a.c. power into d.c. power |
| B. | d.c. power into a.c. power |
| C. | mechanical power into a.c. power |
| D. | none of the above |
| Answer» C. mechanical power into a.c. power | |
| 16. |
One condition for oscillation is ___________ |
| A. | A phase shift around the feedback loop of 180° |
| B. | A gain around the feedback loop of one-third |
| C. | A phase shift around the feedback loop of 0° |
| D. | A gain around the feedback loop of less than 1 |
| Answer» D. A gain around the feedback loop of less than 1 | |
| 17. |
An oscillator differs from an amplifier because it |
| A. | Has more gain |
| B. | Requires no input signal |
| C. | Requires no d.c. supply |
| D. | Always has the same input |
| Answer» C. Requires no d.c. supply | |
| 18. |
A Wien bridge oscillator uses ___________ feedback |
| A. | Only positive |
| B. | Only negative |
| C. | Both positive and negative |
| D. | None of the above |
| Answer» D. None of the above | |
| 19. |
The crystal oscillator frequency is very stable due to ___________ of the crystal |
| A. | Rigidity |
| B. | Vibrations |
| C. | Low Q |
| D. | High Q |
| Answer» E. | |
| 20. |
Hartley oscillator is commonly used in ___________ |
| A. | Radio receivers |
| B. | Radio transmitters |
| C. | TV receivers |
| D. | None of the above |
| Answer» B. Radio transmitters | |
| 21. |
In a certain oscillator Av = 50. The attention of the feedback circuit must be ___________ |
| A. | 1 |
| B. | 1 |
| C. | 10 |
| D. | 2 |
| Answer» E. | |
| 22. |
Quartz crystal is most commonly used in crystal oscillators because ___________ |
| A. | It has superior electrical properties |
| B. | It is easily available |
| C. | It is quite inexpensive |
| D. | None of the above |
| Answer» B. It is easily available | |
| 23. |
In an LC oscillator, the frequency of oscillator is ___________ L or C. |
| A. | Proportional to square of |
| B. | Directly proportional to |
| C. | Independent of the values of |
| D. | Inversely proportional to square root of |
| Answer» E. | |
| 24. |
An oscillator employs ___________ feedback |
| A. | Positive |
| B. | Negative |
| C. | Neither positive nor negative |
| D. | Data insufficient |
| Answer» B. Negative | |
| 25. |
The signal generator generally used in the laboratories is ___________ oscillator |
| A. | Wien-bridge |
| B. | Hartely |
| C. | Crystal |
| D. | Phase shift |
| Answer» B. Hartely | |
| 26. |
In a phase shift oscillator, we use ___________ RC sections |
| A. | Two |
| B. | Three |
| C. | Four |
| D. | None of the above |
| Answer» C. Four | |
| 27. |
An LC oscillator cannot be used to produce ___________ frequencies |
| A. | High |
| B. | Audio |
| C. | Very low |
| D. | Very high |
| Answer» D. Very high | |
| 28. |
An oscillator produces___________ oscillations |
| A. | Damped |
| B. | Undamped |
| C. | Modulated |
| D. | None of the above |
| Answer» C. Modulated | |
| 29. |
WHAT_IS_THE_AVERAGE_VALUE_OF_SATURATION_FACTOR_IN_A_PRACTICAL_CIRCUIT??$ |
| A. | 1 |
| B. | 0 |
| C. | 2 |
| D. | 3 |
| Answer» B. 0 | |
| 30. |
An_oscillator_requires_an_input_voltage_of_high_amplitude.$ |
| A. | True |
| B. | False |
| Answer» C. | |
| 31. |
Barkhausen criteria states phase of loop gain must be 0 for a self sustaining oscillator? |
| A. | True |
| B. | False |
| Answer» B. False | |
| 32. |
Which of the following expression depicts Barkhausen criteria? |
| A. | Aβ = 1 |
| B. | Aβ = 0 |
| C. | Aβ < 1 < Aβ |
| D. | Aβ < 1 |
| Answer» B. A‚âà√≠‚Äö√¢¬ß = 0 | |
| 33. |
For practical oscillators, which law has to be obeyed? |
| A. | Faraday law |
| B. | Hertz law |
| C. | Fleming law |
| D. | Barkhausen law |
| Answer» E. | |
| 34. |
For an oscillator, input voltage is 5V, loop gain is 2, find output voltage? |
| A. | 10 |
| B. | 20 |
| C. | 5 |
| D. | 15 |
| Answer» B. 20 | |
| 35. |
What is the value of input voltage, if Aβ=1 and input voltage is 5V?$ |
| A. | 0 |
| B. | 2 |
| C. | 5 |
| D. | 10 |
| Answer» D. 10 | |
| 36. |
What is the value of self-oscillating circuits? |
| A. | 0 |
| B. | 1 |
| C. | 2 |
| D. | 3 |
| Answer» C. 2 | |
| 37. |
Give the relation between output and input voltage of an oscillator? |
| A. | A<sub>v</sub> = V<sub>i</sub>/V<sub>o</sub> |
| B. | V<sub>i</sub> = V<sub>o</sub> A<sub>v</sub> |
| C. | V<sub>o</sub> = A<sub>v</sub>/V<sub>i</sub> |
| D. | A<sub>v</sub> = V<sub>o</sub>/V<sub>i</sub> |
| Answer» E. | |
| 38. |
What are oscillators? |
| A. | Switching circuits |
| B. | Converts dc to ac |
| C. | Converts ac to dc |
| D. | Filter circuits |
| Answer» C. Converts ac to dc | |