3 – Op Amp: Characteristic Equation And Curve

Here's an example that demonstrates it.

Assume that an Operational Amplifier is characterized by an open-loop gain equal to 10 (we will soon see that the gain of an Op-Amp is characterized by real values even higher).

Assume also two different cases for inputs.

First case:

$V_{+}=0.75Volt$

$V_{-}=0Volt$

Second case:

$V_{+}=1.5Volt$

$V_{-}=0.75Volt$

In both cases differential voltage input is equal to:

$v_{D}=V_{+}-V_{-}=0.75Volt$

And in both cases voltage output is equal to:

$V_{OUT}=A\cdot v_{D}=10\cdot 0.75=7.5Volt$

Next image shows graphically the model's meaning: