Tag: the operational amplifier (op-amp)

Open loop voltage in an opamp is very high and hence option d is the correct option

1. Virtual ground refers to a circuit elements that is not connected to the ground directly, it is held at a reference voltage. This reference voltage need not to be same voltage as ground either.
   2. While in all other ground it may be mechanical A.C or an ordinary ground it act as a reference point against which other voltage can be measured.
   3. The key point  is that the current flow from one point of the circuit through ground then back into the circuit.
   So, current cannot flow to ground through a virtual ground.

Open loop configuration of Op-amp may increase the threat of distortion as well as clipping of output signal. Due to this reason, the output gets switched between the positive and negative saturation levels.

Hence, this is the major drawback because of which it is highly impossible to use Op-amps with open loop configurations in linear circuit applications.

the closed loop gain is given by $A _{cl}=\dfrac{A}{1+A \beta}$. since the open loop gain is large, the closed loop gain almost remains a constant, as it will be independent of open loop gain 

Input current in an ideal operational amplifier   $i = \dfrac{V}{Z}$
Since,  input impedance of the ideal operational amplifier is infinite  $i.e. Z = \infty$
$\implies \ i =\dfrac{V}{\infty}= 0$