The action of backward wave oscillator is similar to that of klystron amplifier

CuriousTab

Home Aptitude

Correct Answer

TWT

Explanation

It is somewhat similar to TWT and can deliver microwave power over a wide frequency band.

It has an electron gun and a helix structure. However the interaction between electron beam and RF wave is different than in TWT.

The growing RF wave travels in opposite direction to the electron beam.

The frequency of wave can be changed by changing the voltage which controls the beam velocity.

Moreover the amplitude of oscillations can be decreased continuously to zero by changing the beam current.

It features are:

1. Frequency range - 1 GHz to 1000 GHz.

2. Power output - 10 mV to 150 mW (continuous wave) 250kW (pulsed).

It is used as signal source in transmitters and instruments.

1. Assertion (A): Inverters and choppers use fast switching thyristors
Reason (R): Fast switching SCR has low turn off time.
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

2. Match the following:

3. Assertion (A): A small section of high impedance line is equivalent to a series inductance.
Reason (R): A small section of a low impedance line is equivalent to a series resistance.
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

4. Assertion (A): Two equal and opposite travelling waves result in a standing wave.
Reason (R): The ratio of maximum to minimum value of a standing wave is called SWR.
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

6. Match the following:

7. Match the following:

	List I (Operation in Basic)		List II (Priority)
A.	Exponentiation	1.	1
B.	Multiplication and division	2.	2
C.	Addition and subtraction	3.	3
D.	Expression within parenthesis	4.	4

8. Match the following:

	List I (Double Rectifier)		List II (Number of Diodes)
A.	Full wave Bridge rectifier	1.	1
B.	Half wave rectifier	2.	2
C.	Full wave rectifier using centre tapped transformer	3.	4

9. Match the following:

	List I (BJT amplifier)		List II (Characteristics)
A.	CE	1.	good voltage gain, good current gain
B.	CC	2.	voltage gain less than 1, high current gain
C.	CB	3.	current gain less than 1, voltage gain high

10. A parallel plate capacitor has area of plate equal to 1 m and distance between plates is also 1 m². The lossy dielectric has a complex dielectric constant ?_r = ?'_r - j ?"_r. If the capacitor is represented by R and C is parallel, then
Options
A.
B.
C.
D.