Hi,

would you pls let me know why ac=1(magnitude) while doing ac simulation?

THanks

Essentially if you're doing a linear small signal analysis, it doesn't matter what magnitude the input signal is - the gains will always be the same.

You could choose to put a realistic signal magnitude at the input, and then you'll get a realistic signal at the output, and could then calculate the gain by dividing the output signal by the input signal. By setting the input signal to 1, you directly get the gain (from the input source) at the node you plot.

Regards,

Andrew.