Help measuring gain...

Thread Starter

circuitnub

Joined Apr 27, 2009
2
I have a cascade of two BJT transistors, and I'm trying to make the gain be within a certain range. I am using PSPICE and I'm not sure how to tell what the gain is at a certain frequency. How do I check?
 
The voltage gain is simply the output voltage over the input voltage.

A = Vout/Vin

There are several ways you can do it in PSPICE. You can input a given frequency and watch the response of the circuit over a given period of time. Compare the magnitude of the output signal to the input signal.

A second way to do it is to perform an AC Sweep. It allows you to select a beginning frequency, an end frequency, and number of points you would like to simulate. A graph of the output can be plotted to show the gain.

Here is a website that shows have to do it in one version of SPICE. Yours may or may not be similar but it might help a little.

http://notes.ump.edu.my/fkee/Analog...AC Sweep (Frequency) Simulation in PSpice.pdf
 
Last edited:

CDRIVE

Joined Jul 1, 2008
2,219
Most Spice programs provide both DC Transfer Characteristic and AC Transfer Characteristic used for this purpose.
 
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