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DIY Stompboxes => Building your own stompbox => Topic started by: Athin on August 15, 2004, 04:08:42 AM

Title: [OT] LTSpice pot model
Post by: Athin on August 15, 2004, 04:08:42 AM
Hi,
   I've been using LTSpice for some time now and the lack of a potentiometer symbol is a pain in the back... So I decided to make my own, but this spice thing ain't as easy as it seems. Drawing the symbol ain't a problem, but how do I make the model?
Title: [OT] LTSpice pot model
Post by: spongebob on August 15, 2004, 06:35:03 AM
There is a yahoo user group for LTSpice at http://groups.yahoo.com/group/LTspice, you can download a potentiometer library from there (you need to "subscribe" to the group first), look under "Files/Tutorials".

For example the linear potentiometer looks like this:

.SUBCKT pot_lin 1 2 3
.param w=limit(0.01m,wiper,0.99999)
*
R1 1 3 {Rtot*(1-w)}
R2 3 2 {Rtot*(w)}
.ENDS

There are also a lot of other useful components on that page...
Title: [OT] LTSpice pot model
Post by: Athin on August 15, 2004, 10:02:37 AM
thanx, I had no idea of that group...
nice to see a fellow ltspice user... R U running Linux?
Title: [OT] LTSpice pot model
Post by: spongebob on August 16, 2004, 02:56:09 AM
Quote from: Athinnice to see a fellow ltspice user... R U running Linux?

Linux? No, I have Win XP on my machine, although we are working with Linux workstations at university, so I know a few things about it.

From all the different Spice type programs I like LTSpice the most, small installation footprint, fast, and free!

Have you tried the wavein / waveout demo files? It shows how to use an audio file as a signal source and how to record a signal at some point in the circuit. That way you can "preview" (acoustically) the effect of diode clipping etc., but the calculations can take a long time...