MCQOPTIONS
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MCQOPTIONS
This section includes 657 Mcqs, each offering curated multiple-choice questions to sharpen your Testing Subject knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
In a full wave diode rectifier circuit each diode carries current for |
| A. | 90° in each cycle |
| B. | 180° in each cycle |
| C. | 270° in each cycle |
| D. | 360° in each cycle |
| Answer» C. 270° in each cycle | |
| 2. |
A non-inverting voltage feedback amplifier is a |
| A. | voltage amplifier |
| B. | current amplifier |
| C. | current to voltage converter |
| D. | voltage to current converter |
| Answer» B. current amplifier | |
| 3. |
Assertion (A): Negative feedback reduces the gain of an amplifierReason (R): Negative feedback is very commonly used in amplifier circuits |
| A. | Both A and R are correct and R is correct explanation for A |
| B. | Both A and R are correct but R is not correct explanation for A |
| C. | A is correct R is wrong |
| D. | A is wrong R is correct |
| Answer» C. A is correct R is wrong | |
| 4. |
A bridge diode circuit using ideal diodes has in input voltage of 20 sin ωt volts. The average and rms values of output voltage are |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» B. B | |
| 5. |
In a CE amplifier circuit, the output voltage |
| A. | is very small |
| B. | is always constant |
| C. | depends on β |
| D. | none of the above |
| Answer» D. none of the above | |
| 6. |
A generator with an internal resistance of 600 Ω drives an amplifier whose input resistance is 400 Ω. The generator's open circuit voltages is 1 mV; the amplifier develops 100mV across an 8kΩ load. The input voltage to the amplifier is |
| A. | 0.1 m V |
| B. | 0.4 m V |
| C. | 1 m V |
| D. | 4 m V |
| Answer» C. 1 m V | |
| 7. |
Consider the following statements :The lower cut off frequencies of an RC coupled amplifier depend on1. input and output coupling capacitor2. emitter by pass capacitors3. junction capacitances Which of the above are correct? |
| A. | 1 only |
| B. | 2 only |
| C. | 1 and 2 |
| D. | 2 and 3 |
| Answer» B. 2 only | |
| 8. |
The most common method for biasing a JFET is |
| A. | reverse bias |
| B. | self bias |
| C. | voltage divider bias |
| D. | none of the above |
| Answer» C. voltage divider bias | |
| 9. |
In every practical oscillator, the loop gain is slightly larger than unity and the amplitude of the oscillations is limited by the |
| A. | magnitude of the loop gain |
| B. | onset if non-linearity |
| C. | magnitude of gain of the amplifier |
| D. | feedback transmission factor |
| Answer» C. magnitude of gain of the amplifier | |
| 10. |
In the circuit of the given figure, assume that the diodes are ideal and the meter is an average indicating ammeter, the ammeter will read |
| A. | 0.4√2 A |
| B. | 0.4 A |
| C. | 0.8/π A |
| D. | 0.4/π mA |
| Answer» E. | |
| 11. |
A generator with an internal resistance of 600 Ω drives an amplifier whose input resistance is 400 Ω. The generator's open circuit voltages is 1 mV; the amplifier develops 100mV across an 8kΩ load. The current amplification is |
| A. | 2.5 |
| B. | 12.5 |
| C. | 25 |
| D. | 125 |
| Answer» C. 25 | |
| 12. |
The given circuit has a feedback factor of |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» E. | |
| 13. |
A FET has |
| A. | very high input resistance |
| B. | very low input resistance |
| C. | high connection emitter junction |
| D. | forward biased PN junction |
| Answer» B. very low input resistance | |
| 14. |
A JFET is a |
| A. | unipolar device |
| B. | bipolar device |
| C. | tripolar device |
| D. | none of the above |
| Answer» B. bipolar device | |
| 15. |
The main advantage of CMOS circuit is |
| A. | high gain |
| B. | high output impedance |
| C. | low power consumption |
| D. | high gain and high output impedance |
| Answer» D. high gain and high output impedance | |
| 16. |
The voltage gain of an amplifier without and with feedback are 100 and 20. The negative feedback is |
| A. | 4% |
| B. | 5% |
| C. | 20% |
| D. | 80% |
| Answer» B. 5% | |
| 17. |
A transistor has two p-n junctions. The batteries should be connected such that |
| A. | both junctions are forward biased |
| B. | both junctions are reverse biased |
| C. | one junction is forward biased and the other is reverse biased |
| D. | either (a) or (b) |
| Answer» D. either (a) or (b) | |
| 18. |
A full wave rectifier circuit using centre tapped transformer and a bridge rectifier are fed at 100 V, 50 Hz. The frequencies of outputs in these two rectifiers are |
| A. | 100 Hz each |
| B. | 50 Hz each |
| C. | 100 Hz and 50 Hz |
| D. | 50 Hz and 100 Hz |
| Answer» B. 50 Hz each | |
| 19. |
In a transistor amplifier, the reverse saturation current Iᴄᴑ |
| A. | Doubles for every 10°C rise in temperature |
| B. | Doubles for every 20°C rise in temperature |
| C. | Increase 100°C with temperature |
| D. | Doubles for every 5°C rise in temperature |
| Answer» B. Doubles for every 20°C rise in temperature | |
| 20. |
The mobility of e- for Ge and Si respectively is |
| A. | 1.66, 2.5 |
| B. | 2.5, 1.66 |
| C. | 2.7, 2.33 |
| D. | 2.33, 2.7 |
| Answer» B. 2.5, 1.66 | |
| 21. |
The period of oscillation of a symmetrical multivibrator depends upon the discharging time constant and is roughly given by |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» B. B | |
| 22. |
Assertion (A): A Darlington amplifier has very low output impedanceReason (R): The circuit has a low resistance RE between emitter and ground |
| A. | Both A and R are correct and R is correct explanation for A |
| B. | Both A and R are correct but R is not correct explanation for A |
| C. | A is correct R is wrong |
| D. | A is wrong R is correct |
| Answer» D. A is wrong R is correct | |
| 23. |
The bandwidth of an amplifier can be reduced by |
| A. | miller effect compensation |
| B. | pole zero compensation |
| C. | dominant pole compensation |
| D. | lead compensation |
| Answer» D. lead compensation | |
| 24. |
In a CE amplifier circuit the emitter by pass capacitor is remove. The ac output voltage |
| A. | increases |
| B. | remains the same |
| C. | increases or decreases |
| D. | decreases |
| Answer» E. | |
| 25. |
In a rectifier circuit the filter capacitance is increased. Then the ripple will |
| A. | increase |
| B. | decrease |
| C. | remain the same |
| D. | either (a) or (b) |
| Answer» C. remain the same | |
| 26. |
The signal input to a given amplifier is made up of 100 mΩ signal power and 1 mΩ noise power. The amplifier contributes an additional 100 mΩ of noise and has a power gain of 20 dB. The output signal-to-noise ratio is |
| A. | 100 |
| B. | 50 |
| C. | 10 |
| D. | 5 |
| Answer» C. 10 | |
| 27. |
A Wien bridge is suitable for |
| A. | audio frequencies only |
| B. | radio frequencies only |
| C. | both audio and radio frequencies |
| D. | very low frequencies only |
| Answer» B. radio frequencies only | |
| 28. |
CMRR of a difference amplifier is equal to |
| A. | (Av')/(Acom) |
| B. | Av/Acom |
| C. | Acom/Av' |
| D. | (Av)/(Acom)² |
| Answer» B. Av/Acom | |
| 29. |
In graphical analysis of BJT amplifier the slope of ac line is more than that of dc load line. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» B. False | |
| 30. |
In a push pull circuit |
| A. | each transistor conducts for 180° |
| B. | each transistor conducts for more than 180° but less than 360° |
| C. | each transistor conducts for less than 180° |
| D. | the period of conduction of each transistor depends on circuit configuration |
| Answer» B. each transistor conducts for more than 180° but less than 360° | |
| 31. |
The main disadvantage of a JFET is |
| A. | low gain-bandwidth product |
| B. | high noise level |
| C. | high cost |
| D. | low gain |
| Answer» B. high noise level | |
| 32. |
Figure uses 10 V zener diode. The minimum and maximum current through series resistance are |
| A. | 10 mA and 30 mA |
| B. | 20 mA and 40 mA |
| C. | 0 and 30 mA |
| D. | 0 and 40 mA |
| Answer» B. 20 mA and 40 mA | |
| 33. |
Saturation of iron core causes distortion. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» B. False | |
| 34. |
Which op-amp circuit uses a resistance in series with input and capacitor in feedback path? |
| A. | Differentiating amplifier |
| B. | Integrating amplifier |
| C. | Logarithmic amplifier |
| D. | Exponential amplifier |
| Answer» C. Logarithmic amplifier | |
| 35. |
Which distortion is least objectionable in case of audio amplifiers? |
| A. | Phase distortion |
| B. | Frequency distortion |
| C. | Harmonic distortion |
| D. | Inter-modulation distortion |
| Answer» B. Frequency distortion | |
| 36. |
Figure shows the feedback network of one of the very popular types of sinusoidal oscillators. Which one is that? |
| A. | Weinbridge oscillator |
| B. | Hartley oscillator |
| C. | Colpitt's oscillator |
| D. | R-C phase shift oscillator |
| Answer» B. Hartley oscillator | |
| 37. |
DC amplifiers have a tendency to be unstable. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» B. False | |
| 38. |
A voltage doubler circuit uses |
| A. | two diodes |
| B. | two capacitors |
| C. | two diodes and two capacitors |
| D. | none of the above |
| Answer» D. none of the above | |
| 39. |
In a class C operation |
| A. | VCC is much larger than VCE(sat) |
| B. | VCC is much smaller than VCE(sat) |
| C. | VCC and VCE(sat) are nearly equal |
| D. | none of the above |
| Answer» B. VCC is much smaller than VCE(sat) | |
| 40. |
An op-amp uses |
| A. | RC coupling |
| B. | direct coupling |
| C. | transformer coupling |
| D. | either (b) or (c) |
| Answer» C. transformer coupling | |
| 41. |
Two identical FETs, each characterised by the parameters gm and rd are connected in parallel. The composite FET is then characterised by the parameters |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» D. D | |
| 42. |
In an RC-coupled amplifier for improving the low frequency response |
| A. | lower RL is provided |
| B. | more bias is used |
| C. | less gain is provided |
| D. | higher CC is used |
| Answer» E. | |
| 43. |
Three cascaded stages have gains of 10, 20 and 25. The overall gain will be |
| A. | 10 |
| B. | 55 |
| C. | 500 |
| D. | 5000 |
| Answer» E. | |
| 44. |
The configuration of figure is a |
| A. | Hartley oscillator |
| B. | Precision Integrator |
| C. | Wienbridge oscillator |
| D. | Butterworth high pass filter |
| Answer» D. Butterworth high pass filter | |
| 45. |
The parameter β of a BJT change by 300%. If self bias is used in the amplifier using this BJT, the quiescent value of IC and VCE remain almost the same. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» B. False | |
| 46. |
Assertion (A): A dc stabilizer has constant output voltage irrespective of variations in input voltage and load currentReason (R): A dc series regulator uses a zener diode across the load to stabilize the output voltage. |
| A. | Both A and R are correct and R is correct explanation for A |
| B. | Both A and R are correct but R is not correct explanation for A |
| C. | A is correct R is wrong |
| D. | A is wrong R is correct |
| Answer» C. A is correct R is wrong | |
| 47. |
A half wave diode rectifier uses a diode having forward resistance of 50 ohms. The load resistance is also 50 ohms. Then the voltage regulation is |
| A. | 20% |
| B. | 50% |
| C. | 100% |
| D. | 200% |
| Answer» D. 200% | |
| 48. |
Which of the following statement about JFET is correct? |
| A. | In an N-channel JFET, the channel is the narrowest under zero gate bias condition |
| B. | In a JFET the gates are always forward biased |
| C. | In a JFET, gate-source cut off voltage is numerically equal to the pinch off voltage |
| D. | It is a voltage controlled device |
| Answer» D. It is a voltage controlled device | |
| 49. |
To prevent a DC return between source and load, it is necessary to use |
| A. | resistor between source and load |
| B. | inductor between source and load |
| C. | capacitor between source and load |
| D. | either (a) or (b) |
| Answer» D. either (a) or (b) | |
| 50. |
A ripple in collector supply voltage of the output stage of amplifier causes noise. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» B. False | |