An amplifier has an open-loop gain of 200 and a feedback of 0.1. If the open-loop gain changes by 10% due to temperature, the change in the closed loop gain is __________.

Question

Question

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KVS TGT WET (Work Experience Teacher) 8 Jan 2017 Official Paper

Answer 1

The correct answer is option 1
Concept:

Here, A = 200, β = 0.1, dA/A = 10% = 0.1

\(Now,\frac{{dA'}}{{A'}} = \frac{1}{{\beta A}}.\frac{{dA}}{A} = \frac{1}{{0.1 \times 200}} \times 10\% = 0.5\%\)

It is seen that while the amplifier gain changes by 10%, the feedback gain changes by only 0.5% i.e. an improvement of 10/0.5 = 20 times.