Page 14 of 15

#196

Posted: Fri Mar 22, 2013 4:19 pm
by IslandPink
Thanks Mike .
It would therefore help if there was a comment in 'resistor' and 'capacitor' pages to look also under 'Introduction/General structure and conventions' !

Other thread :
http://www.audio-talk.co.uk/phpBB2/view ... &start=105

#197

Posted: Fri Mar 22, 2013 5:05 pm
by Mike H
Ah right OK.

#198

Posted: Wed Apr 17, 2013 6:53 pm
by IslandPink
When I plot frequency scans of things like AC current on different components, the curves for the value (mA ) and the phase (deg) are coming out as solid lines in both cases. How do I get the phase line to be dotted, so I can see what's going on more easily ?
Not been able to fix this so far, after about 30 mins of fiddling and searching with google .

#199

Posted: Wed Apr 17, 2013 8:27 pm
by Mike H
Can you show us what the plots display looks like?

Menu: Plot Settings > Reset Colors ?

#200

Posted: Wed Apr 17, 2013 9:50 pm
by IslandPink
Here we go :
(Display colour only changes the colours of the lines ; I also expected it to have things like dashed or solid or dotted line for the phase plots, too ) .

#201

Posted: Wed Apr 17, 2013 10:08 pm
by Nick
Looking at that the phase is dotted, I think your display is having problems resolving it. More viable at the LF end.

#202

Posted: Wed Apr 17, 2013 11:20 pm
by IslandPink
Actually you're right - well spotted .
If the window is maximised on Spice it's just about visible.
It actually looks clearer in the .jpg I created to throw up on this thread, weirdly .
I wish I could make it a bit more obviously dashed in Spice though .

#203

Posted: Thu Apr 18, 2013 3:03 pm
by Mike H
Oh yes I see, it is doing it, just not resolved very well.

#204

Posted: Tue Mar 04, 2014 5:34 pm
by slowmotion
I finally read this thread, downloaded LTspice and followed the instructions
and tried out the simulations. Thanks to all!

#205

Posted: Wed Mar 05, 2014 6:35 pm
by IslandPink
It's a very cool thing , a great back-up to the real building .

#206 Re: What is SPICE

Posted: Wed Jun 23, 2021 1:02 pm
by Max N
Hi, wasn't sure of the best place to ask this.....
I'm a complete novice at LTSpice. First of all, many thanks to everyone who has posted helpful tips in this and other threads.
I've drafted a PP 6B4G (well actually 2A3) output stage and got it running with resistor loading. I'm now trying to model a push-pull OPT, I have a figure for the primary inductance - should I just put half of this figure for each primary winding?
Is this of interest to anyone else? I could post the file here when it's done (might need a bit of help)

#207 Re: What is SPICE

Posted: Wed Jun 23, 2021 1:10 pm
by Max N
For reference, I am trying to model this transformer
http://www.monolithmagnetics.com/sites/ ... prelim.pdf

#208 Re: What is SPICE

Posted: Thu Jun 24, 2021 1:50 pm
by Max N
Well, I've had a go but it looks to me like the HF roll-off happens way too early, and the LF roll off isn't there at all......
LTspice PP transformer freq sweep.PNG
LTspice PP transformer freq sweep.PNG (52.16 KiB) Viewed 9408 times

#209 Re: What is SPICE

Posted: Thu Jun 24, 2021 5:24 pm
by Nick
Thats because a leakage inductance coefficient of 0.97 is defining a crap transformer. 1 is perfect, start there.

http://ltwiki.org/?title=Transformers

#210 Re: What is SPICE

Posted: Thu Jun 24, 2021 6:38 pm
by Max N
OK thanks Nick will give that a go :-)