**TRANSISTOR TUNED AMPLIFIERS Questions and Answers pdf :-**

1. A tuned amplifier uses ……………. load

Resistive

Capacitive

LC tank

Inductive

Ans : 3

2. A tuned amplifier is generally operated in ……………. operation

Class A

Class C

Class B

None of the above

Ans : 2

3. A tuned amplifier is used in …………… applications

Radio frequency

Low frequency

Audio frequency

None of the above

Ans : 1

4. Frequencies above …………… kHz are called radio frequencies

2

10

50

200

Ans : 4

5. At series or parallel resonance, the circuit power factor is …………..

0

5

1

8

Ans : 3

6. The voltage gain of a tuned amplifier is ……………. at resonant frequency

Minimum

Maximum

Half-way between maximum and minimum

Zero

Ans : 2

7. At parallel resonance, the line current is ……………….

Minimum

Maximum

Quite large

None of the above

Ans : 1

8. At series resonance, the circuit offers …………….. impedance

Zero

Maximum

Minimum

None of the above

Ans : 3

9. A resonant circuit contains ……………… elements

R and L only

R and C only

Only R

L and C

Ans : 4

10. At series or parallel resonance, the circuit behaves as a …………….. load

Capacitive

Resistive

Inductive

None of the above

Ans : 2

11. At series resonance, voltage across L is ………………. voltage across C

Equal to but opposite in phase to

Equal to but in phase with

Greater than but in phase with

Less than but in phase with

Ans : 1

12. When either L or C is increased, the resonant frequency of LC circuit ……………

Remains the same

Increases

Decreases

Insufficient data

Ans : 3

13. At parallel resonance, the net reactive component circuit current is …………

Capacitive

Zero

Inductive

None of the above

Ans : 2

14. In parallel resonance, the circuit impedance is …………..

C/LR

R/LC

CR/L

L/CR

Ans : 4

15. In a parallel LC circuit, if the input signal frequency is increased above resonant frequency then …………………..

XL increases and XC decreases

XL decreases and XC increases

Both XL and XC increase

Both XL and XC decrease

Ans : 1

16. The Q of an LC circuit is given by ………………….

2pfr x R

R / 2pfrL

2pfrL / R

R2/2pfrL

Ans : 3

17. If Q of an LC circuit increases, then bandwidth …………………

Increases

Decreases

Remains the same

Insufficient data

Ans : 2

18. At series resonance, the net reactive component of circuit current is ……………….

Zero

Inductive

Capacitive

None of the above

Ans : 1

19. The dimensions of L/CR are that of …………….

Farad

Henry

Ohm

None of the above

Ans : 3

20. If L/C ratio of a parallel LC circuit is increased, the Q of the circuit ……………..

Is decreased

Is increased

Remains the same

None of the above

Ans : 2

21. At series resonance, the phase angle between applied voltage and circuit is ………..

90o

180o

0o

None of the above

Ans : 3

22. At parallel resonance, the ratio L/C is …………….

Very large

Zero

Small

None of the above

Ans : 1

23. If the resistance of a tuned circuit is increased, the Q of the circuit ………….

Is increased

Is decreased

Remains the same

None of the above

Ans : 2

24. The Q of a tuned circuit refers to the property of …………..

Sensitivity

Fidelity

Selectivity

None of the above

Ans : 3

25. At parallel resonance, the phase angle between the applied voltage and circuit current is …………….

90o

180o

0o

None of the above

Ans : 3

26. In a parallel LC circuit, if the signal frequency is decreased below the resonant frequency, then ……………

XL decreases and XC increases

XL increases and XC decreases

Line current becomes minimum

None of the above

Ans : 1

27. In series resonance, there is ………………

Voltage amplification

Current amplification

Both voltage and current amplification

None of the above

Ans : 1

28. The Q of a tuned amplifier is generally …………….

Less than 5

Less than 10

More than 10

None of the above

Ans : 3

29. The Q of a tuned amplifier is 50. If the resonant frequency for the amplifier is 1000kHZ, then bandwidth is …………

10kHz

40 kHz

30 kHz

20 kHz

Ans : 4

30. In the above question, what are the values of cut-off frequencies?

140 kHz , 60 kHz

1020 kHz , 980 kHz

1030 kHz , 970 kHz

None of the above

Ans : 2

31. For frequencies above the resonant frequency, a parallel LC circuit behaves as a ……………. load

Capacitive

Resistive

Inductive

None of the above

Ans : 1

32. In parallel resonance, there is …………

Both voltage and current amplification

Voltage amplifications

Current amplification

None of the above

Ans : 3

33. For frequencies below resonant frequency, a series LC circuit behaves as a ………… load

Resistive

Capacitive

Inductive

None of the above

Ans : 2

34. If a high degree of selectivity is desired, then double-tuned circuit should have …………. coupling

Loose

Tight

Critical

None of the above

Ans : 1

35. In the double tuned circuit, if the mutual inductance between the two tuned circuits is decreased, the level of resonance curve ………..

Remains the same

Is lowered

Is raised

None of the above

Ans : 3

36. For frequencies above the resonant frequency , a series LC circuit behaves as a ………….. load

Resistive

Inductive

Capacitive

None of the above

Ans : 2

37. Double tuned circuits are used in ……………. stages of a radio receiver

IF

Audio

Output

None of the above

Ans : 1

38. A class C amplifier always drives ………. load

A pure resistive

A pure inductive

A pure capacitive

A resonant tank

Ans : 4

39. Tuned class C amplifiers are used for RF signals of ………………

Low power

High power

Very high power

None of the above

Ans : 4

40. For frequencies below the resonant frequency , a parallel LC circuit behaves as a …………… load

Inductive

Resistive

Capacitive

None of the above

Ans : 1