Electronics and Communication Engineering - Electronic Devices and Circuits - Discussion
Discussion Forum : Electronic Devices and Circuits - Section 1 (Q.No. 22)
22.
An amplifier without feedback has a voltage gain of 50, input resistance of 1 kΩ and output resistance of 2.5 kΩ. The input resistance of the current shunt -ve feedback amplifier using the above amplifier with a feedback factor of 0.2 is
Answer: Option
Explanation:
Input Resistance with feedback for current shunt, 
.
Discussion:
11 comments Page 2 of 2.
RAM PRASAD said:
1 decade ago
Here it is current shunt feedback hence need to convert current gain then calculate input resistance.
AV = AI*RL/RI FROM THAT AI = 20.
RI( WITH FEEDBACK) = RI/(1+AI*BETA) = 1/(1+20*02) = 1/5.
AV = AI*RL/RI FROM THAT AI = 20.
RI( WITH FEEDBACK) = RI/(1+AI*BETA) = 1/(1+20*02) = 1/5.
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