Hi,
Replaced the Xaxis parameter with Ic(Q1).
E

Cleaned up the waveform display

 

What is the d in "d(Ic(Q1))" in those plots? I guessed time-derivative, but isn't that ddt ?

 

Hi RRR,
Open standard.bjt and insert the attached text.
You will have to close LTS and restart to get the My2N2222A active.
E

This is the plot now. Zero AC plot. How do you change the x-axis parameter?
RS

 

Hi,
The AC plot works for me.
When posting asc file plots always post the asc file, so that we can see what you have in your circuit.
E

 

Hi,
The AC plot works for me.
When posting asc file plots always post the asc file, so that we can see what you have in your circuit.
E
View attachment 302871

Here is th asc file.

 

Hi RRR,
This is your asc file.
E

 

Hi
For Ic(Q1)
Click on the Xaxis and type in Ic(Q1)
E

 

Hi
For Ic(Q1)
Click on the Xaxis and type in Ic(Q1)
E
View attachment 302875A

Thanks for all the great help.
One last question. Why does my plot start at 110μA rather than 1μA?

 

One last question. Why does my plot start at 110μA rather than 1μA?

Hi,
Because you are using different X axis scaling
1uA is for the .dc dec 1u 10m 100
and the other is
Ic(Q1)

Try it and compare
E
Added example.

 

Hi,
Because you are using different X axis scaling
1uA is for the .dc dec 1u 10m 100
and the other is
Ic(Q1)

Try it and compare
E
Added example.

View attachment 302877

Got it. Thanks E.

 

@ericgibbs.
What does the d(Ic(Q1)) curve show?

 

hi alec,
This link gives an an example of an AC plot.
E
https://electronics.stackexchange.c...f-plotting-ac-current-gain-in-ltspice-correct

 

Thanks. It was the syntax I was querying. I hadn't come across just the "d" before in LTS, although I have used the ddt function.

 

Thanks. It was the syntax I was querying. I hadn't come across just the "d" before in LTS, although I have used the ddt function.

Should this sim work for PNP devices?
Beta appears as negative.

 

hi alec,
This link gives an an example of an AC plot.
E
https://electronics.stackexchange.c...f-plotting-ac-current-gain-in-ltspice-correct

thanks E

 

What is the d in "d(Ic(Q1))" in those plots? I guessed time-derivative, but isn't that ddt ?

d() is used in the waveform viewer.
ddt() is used in expressions for a behavioral source.

Check the relevant sections in the help file. Why should it be this way? I have no earthly idea.

 

d() is used in the waveform viewer.

Ah yes. Thanks. I hadn't spotted it amongst the Help.

 

Re post #34. Shouldn't this sim work for PNP BJTs? I must have done something wrong.

 

Shouldn't this sim work for PNP BJTs?

It does if you reverse I1.

 

It does if you reverse I1.

Actually I have tried I1 in both directions and neither way works.