Varactor Diodes MCQ’s

This set of RF & Microwave Circuit Design Multiple Choice Questions & Answers (MCQs) focuses on “Varactor Diodes”.

1. Any semiconductor diode has a junction capacitance varying with reverse bias. If such a diode has microwave characteristics, it is called:
a) IMPATT diode
b) TRAPITT diode
c) SKOTTKY diode
d) None of the mentioned

2. The width of depletion region of a varactor diode ________with increase in reverse bias voltage.
a) Increases
b) Decreases
c) Remains constant
d) None of the mentioned

3. Varactor diode is a semiconductor diode in which the _________ can be varied as a function of reverse voltage of the diode.
a) Junction resistance
b) Junction capacitance
c) Junction impedance
d) None of the mentioned

4. Diffused junction mesa silicon diodes are widely used at microwave frequencies.
a) True
b) False

5. Varactor diodes are operated in _________ region to achieve maximum efficiency possible.
a) Cutoff region
b) Saturation region
c) Reverse saturation region
d) Active region

6. ___________ is an amplifier constructed using a device whose reactance is varied to produce amplification.
a) Travelling wave tube
b) Parametric amplifier
c) Common emitter
d) Klystron amplifier

7. Varactors made of ______ have higher frequency range of operation compared to silicon fabricated varactor diodes.
a) Germanium
b) GaAs
c) GaN
d) None of the mentioned

8. The cutoff frequency for operation of a varactor diode at a specific bias is given by:
a) 1/2πRSCjv
b) 1/2πCSRjv
c) 1/2π√LC
d) None of the mentioned

9. Parametric amplifier is a ________ amplifier.
a) Low noise
b) High gain
c) Low gain
d) High noise

10. Gain of a parametric amplifier in terms of the frequencies involved in their operation is:
a) (fP – fS)/fS
b) fS/ (fP – fS)
c) fP/fS
d) None of the mentioned

11. Parametric amplifiers find their application in long range RADAR and satellite ground stations.
a) True
b) False

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