An amplifier without feedback has a voltage gain of 50, input resistance of 1 k?

CuriousTab

CuriousTab

Home Aptitude

Discussion

Home ‣ Electronics and Communication Engineering ‣ Electronic Devices and Circuits Comments

Question
An amplifier without feedback has a voltage gain of 50, input resistance of 1 k? and output resistance of 2.5 k?. The input resistance of the current shunt -ve feedback amplifier using the above amplifier with a feedback factor of 0.2 is
Options
A. 1/11 k?
B. 1/5 k?
C. 5 kW
D. 11 kW

Correct Answer

1/11 k?

Explanation

Input Resistance with feedback for current shunt,

An amplifier without feedback has a voltage gain of 50, input resistance of 1 k? and output resistan

.

Electronic Devices and Circuits problems

Search Results

2. Calculate the stability factor and change in I_C from 25�C to 100�C for, ? = 50, R_B/ R_E = 250, ?I_C0 = 19.9 nA for emitter bias configuration.
Options
A. 42.53, 0.85 ?A
B. 40.91, 0.58 ?A
C. 40.91, 0.58 ?A
D. 41.10, 0.39 ?A

3. Assertion (A): The reverse saturation current in a semiconductor diode is 4nA at 20�C and 32 nA at 50�C.
Reason (R): The reverse saturation current in a semiconductor diode doubles for every 10�C rise in temperature.
Options
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not a correct explanation of A
C. A is true but R is false
D. A is false but R is true

4. A p-n junction diode has
Options
A. low forward and high reverse resistance
B. a non-linear v-i characteristics
C. zero forward current till the forward voltage reaches cut in value
D. all of the above

5. A transistor has a current gain of 0.99 in the CB mode. Its current gain in the CC mode is
Options
A. 100
B. 99
C. 1.01
D. 0.99

6. Work function is the maximum energy required by the fastest electron at 0 K to escape from the metal surface.
Options
A. True
B. False

7. Crossover distortion behaviour is characteristic of
Options
A. class A O/P stage
B. class B O/P stage
C. class AB output stage
D. common pulse O/P state

8. In which of these is reverse recovery time nearly zero?
Options
A. Zener diode
B. Tunnel diode
C. Schottky diode
D. PIN diode

9. The v-i characteristics of a FET is shown in figure. In which region is the device biased for small signal amplification
Options
A. AB
B. BC
C. CD
D. BD

10. In which region of a CE bipolar transistor is collector current almost constant?
Options
A. Saturation region
B. Active region
C. Breakdown region
D. Both saturation and active region

Comments

There are no comments.

More in Electronics and Communication Engineering: