Hi, Ladies and gentlemen:
3ks, I have solved my problem with your help.
I find if you want to get ac current on certain node ,you can use probe. you must set ADE like undermentioned method befor simulation.
Outputs-Save all:
line 1 : Select signals to output(save) all
line 2 : Select power signal to output (pwr) all
line 4: Select device currents(currents) all
line 6 : Select AC terminal currents(useprobes) yes
then we can get AC current plot of any port of any device.
Who can explain the means of above? pls help me.
Now ,I have another problem:
when I simulate the AC current gain of a simple current mirror, how do i get the gain? where is the small signal output signal?
I think, if we want to get AC gain ,we must simulate or compute with small signal circuit, which is difficult for large scale circuit. So, how to simulate the ac gain directlly?