- #1

FOIWATER

Gold Member

- 434

- 12

In the following diff amp, only one output is taken from collector two.

When I calculate the differential mode gain using the second differential input (-Vid/2) I get a positive gain. When I calculate the differential mode gain using the first differential input (Vid/2) I get a negative gain.

A spice simulation of this circuit shows that the output is positive.

I would then expect to get a negative gain for (-vid/2) and a positve gain for (vid/2)

Does someone know why that is not the case?

When I calculate the differential mode gain using the second differential input (-Vid/2) I get a positive gain. When I calculate the differential mode gain using the first differential input (Vid/2) I get a negative gain.

A spice simulation of this circuit shows that the output is positive.

I would then expect to get a negative gain for (-vid/2) and a positve gain for (vid/2)

Does someone know why that is not the case?