Assertion (A): PIN diode is commonly used for microwave control. Reason (R): A P

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Question
Assertion (A): PIN diode is commonly used for microwave control.
Reason (R): A PIN diode uses heavily doped p and n materials.
Options
A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. A is wrong but R is correct

Correct Answer

Both A and R are correct but R is not correct explanation of A

Explanation

A PIN diode has an intrinsic (i) layer between p and n layers. When reverse bias is applied depletion layers are formed at p-i and i-n junctions.

The effective/width of depletion layer increases by the width of i layer. It can be used as a voltage controlled attenuator.

At high frequencies the rectification effect ceases and impedance of diode is effectively that of i layer.

This impedance varies with the applied bias. It is used in high frequency switching circuits, limiters, modulators etc.

Microwave Communication problems

Search Results

1. Assertion (A): A backward wave oscillator can be used as a sweep generator.
Reason (R): The frequency of oscillation of a backward wave oscillator can be changed by varying the voltage which controls the beam velocity.
Options
A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. A is wrong but R is correct

2. In a reflex klystron oscillator, repeller electrode is at
Options
A. low positive potential
B. high positive potential
C. negative potential
D. zero potential

3. In high frequency circuits impedance matching can be done by
1. open circuited stubs
2. short circuited stubs
3. transformer
Which of the above correct?
Options
A. 1, 2 and 3
B. 1 and 2 only
C. 1 and 3 only
D. 2 and 3 only

4. Assertion (A): Gate triggering is the most commonly used method for triggering of an SCR.
Reason (R): Even a small gate current is sufficient to turn on an SCR.
Options
A. Both A and R are correct and R is correct explanation of A
B. Both A and R correct but R is not correct explanation of A
C. A is correct but R is wrong
D. A is wrong but R is correct

6. Assertion (A): The velocity factor of a line is the ratio of wave velocity on the line to speed of light.
Reason (R): If the conductors of a line are immersed in a non magnetic insulating liquid, the wave velocity increases.
Options
A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. A is wrong but R is correct

7. The magnitudes of OC and SC input impedances of a transmission line an 100 ? and 25 ?. The characteristic impedance is
Options
A. 25 ?
B. 50 ?
C. 75 ?
D. 100 ?

8. Assertion (A): A quarter wave transformer is used to match a resistive load to a transmission line.
Reason (R): A quarter wave transformer is a transmission line of quarter wave length.
Options
A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. A is wrong but R is correct

10. The correct sequence of parts in klystron amplifier are
Options
A. anode, catcher cavity, cathode, buncher cavity
B. cathode, buncher cavity, catcher cavity, cavity
C. anode, buncher cavity, catcher cavity, cathode
D. cathode, catcher cavity, anode, buncher cavity

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