Hi all,
I'm trying to get started with using SPICE for simulations and had questions on how the AC Sweep works.
To start (and for simplicity sake), I'm using a very basic common emitter circuit. For the transient test, I am applying a 0.1 V amplitude, 1kHz sine wave on top of a 0.8 V DC source. I can then plot VIN and VOUT to see how the circuit is behaving.
When I run the same setup using the AC source to do an AC Sweep, I see that at 1kHz, I get a gain of -41. How is this gain being calculated at each frequency? Why is the gain negative?
If I use the above transient plots, picking an arbitrary point, I can calculate:
gain= 20 * log(VOUT/VIN) = 14.71
Now, I know this probably isn't right, but this is where I am currently stuck. So I defer to the experts
I really would like to understand more of what's going on. Especially on a qualitative level.
Thanks much!
I'm trying to get started with using SPICE for simulations and had questions on how the AC Sweep works.
To start (and for simplicity sake), I'm using a very basic common emitter circuit. For the transient test, I am applying a 0.1 V amplitude, 1kHz sine wave on top of a 0.8 V DC source. I can then plot VIN and VOUT to see how the circuit is behaving.
When I run the same setup using the AC source to do an AC Sweep, I see that at 1kHz, I get a gain of -41. How is this gain being calculated at each frequency? Why is the gain negative?
If I use the above transient plots, picking an arbitrary point, I can calculate:
gain= 20 * log(VOUT/VIN) = 14.71
Now, I know this probably isn't right, but this is where I am currently stuck. So I defer to the experts
I really would like to understand more of what's going on. Especially on a qualitative level.
Thanks much!
Attachments
-
63.1 KB Views: 30
-
47 KB Views: 25