The Designer's Guide Community
Forum
Welcome, Guest. Please Login or Register. Please follow the Forum guidelines.
Jan 27th, 2021, 1:39am
Pages: 1
Send Topic Print
Active Inductor simulation (Read 1535 times)
blue111
Community Member
***
Offline



Posts: 75

Active Inductor simulation
Aug 09th, 2017, 8:27pm
 
I am using ngspice to simulate active inductor in https://github.com/promach/frequency_trap

why Vtest = -2 ?

Back to top
 
 
View Profile   IP Logged
Geoffrey_Coram
Senior Fellow
******
Offline



Posts: 1987
Massachusetts, USA
Re: Active Inductor simulation
Reply #1 - Aug 11th, 2017, 7:53am
 
Perhaps because of the "ac 2" in the source description for the source Vtest? I can't tell the polarity of the source in the schematic.
Back to top
 
 

If at first you do succeed, STOP, raise your standards, and stop wasting your time.
View Profile WWW   IP Logged
Ken Kundert
Global Moderator
*****
Offline



Posts: 2296
Silicon Valley
Re: Active Inductor simulation
Reply #2 - Aug 11th, 2017, 11:53am
 
It is very strange that AC results would be negative. By the default the magnitude should be shown. Did you ask for the real part to be plotted?

-Ken
Back to top
 
 
View Profile WWW   IP Logged
mhx
New Member
*
Offline



Posts: 7

Re: Active Inductor simulation
Reply #3 - Aug 11th, 2017, 10:02pm
 
> why Vtest = -2 ?

(I wonder: Cs=100uF, Cl=1F?)

In case you are doing this with NGSPICE:
the NGSPICE plot command "plot V(test)"
displays -2. (The real part of V(test)).
This is because the positive terminal of
the AC source is grounded.
Try plot abs(V(test)) instead.

-marcel
Back to top
 
« Last Edit: Aug 12th, 2017, 12:30am by mhx »  
View Profile   IP Logged
blue111
Community Member
***
Offline



Posts: 75

Re: Active Inductor simulation
Reply #4 - Sep 7th, 2017, 9:23pm
 
@mhx

is there a way to put 'plot v_ip_out#branch' inside spice-epilog control directive without any syntax error ?

Note: this only works in ngspice interactive terminal, but not in gschem spice-epilog control directive.

Back to top
 
 
View Profile   IP Logged
Pages: 1
Send Topic Print
Copyright 2002-2021 Designer’s Guide Consulting, Inc. Designer’s Guide® is a registered trademark of Designer’s Guide Consulting, Inc. All rights reserved. Send comments or questions to editor@designers-guide.org. Consider submitting a paper or model.