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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:

first-op-amp-characteristic-curve