Question

A certain inverting amplifier has a closed-loop voltage gain of $25$. The Op-amp has an open-loop voltage gain of \[100,000\] . If an Op-amp with an open-loop voltage gain of \[200,000\] is substituted in the arrangement, the closed-loop gain
A. doubles
B. drops to $12.5$
C. remains at $25$
D. increases slightly

Answer 1

Hint: Here, we have to find the closed-loop gain when an Op-amp with an open-loop voltage gain is \[200,000\]. Also given that a certain inverting amplifier has a closed-loop voltage gain of $25$ and the Op-amp has an open-loop voltage gain of \[100,000\]

Complete step by step solution:
Firstly, we have to define an inverting amplifier. The inverting amplifier is composed of a very limited number of additional electric components called electronic components and it is very easy to design. In a simple form op amp inverting amplifiers require two additional resistors to be used in the electronic circuit to design processes to make a simple and easy to implement still to provide a very high level of performance. It is also used as a virtual earth mixer or summing amplifier. As a summing amplifier the op amp used with audio mixers as well as many other electronic circuits to be designed with voltages need to be summed together. The closed loop is given by \[{A_{closed}} = \dfrac{A}{{1 + \beta A}}\]. And the open loop gain is very large. So, the closed loop remains the same i.e. constant and it is independent of the open loop.

Hence, the correct option is (C).

Note: Hence, in the given question we must be remembered the formula of the closed loop is given by \[{A_{closed}} = \dfrac{A}{{1 + \beta A}}\]. On this basis we can conclude the result of closed loop gain.