LTspice unknown current requested

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Jony130

Joined Feb 17, 2009
5,316
I've tried to simulate the loop gain using this example from this video:

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Buy I received this error message:
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When I tried to plot the loop gain equation
-1/(1-1/(2*(I(LGS:Vi)@1*V(LGS:x)@2-V(LGS:x)@1*I(LGS:Vi)@2)+V(LGS:x)@1+I(LGS:Vi)@2))
Does anyone know how to fix it?
 

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Papabravo

Joined Feb 24, 2006
18,101
But it looks like on Papabravo PC the loop equations work just fine.
Here is a shot of my trace list:
1642361498458.png

You can clearly see that I(lgs:Vi) is a legitimate trace to plot.
Question: I'm running the latest version of LTspice XVII with the following about box. What does yours look like?

1642361630485.png

I must admit that I have not previously encountered the step selection operator denoted by the at symbol '@'. It took me a few seconds to track it down. Thanks for highlighting the usage of this rare animal.
 
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Papabravo

Joined Feb 24, 2006
18,101
Well I'm outa gas for an explanation! I do wonder why my trace list of things to plot is longer than yours.
EDIT: I have 23 items and you have 19. Why do you have missing items?
Also my object code is smaller at 1.57 KB for the same number of matrix opcodes (90).
Only other thing I notice is that your user files are on the "D:" drive rather than the "C:" drive
 
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