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Re: one potentiometer dividing multiple signals

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> If you use a real pot in an analog computer, how do you set the
> coefficients?
>

THAT analog computer has a COEFF mode which activates a Potset signal
line which disconnects the pot input and activates some measurement
circuitry, which in turn shows the setting of the pot as a value between
[-1,1].

If that is not available, another approach is to disconnect the input
and output lines, then connect the input to +1 MU input, and connect
output to meter.

>
> Why not use Spice? I know people who are afraid to use Spice. LT Spice
> is free and I teach people to use it in 10 minutes.
>

One problem is that LT Spice is not available as a package for my Guix
Gnu/Linux computer. Presumably this is because it is not available under
a free software license (FSF definition) and also was designed for
Windows.

I have also little desire to run anything on a desktop simulator, as my
goal is to learn and experiment building simulations/models on my actual
analog computer. THAT is a very nice analog computer, though I found
that the latest model I wanted to experiment with requires a few more
pots and multipliers than I currently have. I built my own expansion
module, adding an extra multiplier, and am pondering building some more
pots and comparator modules. THAT can be daisy chained with another THAT
computer, which is cool, but buying another THAT is about 600 USD.

A year or so ago, I did look a bit into getting some other spice-type
programs that would run on my Guix system. KiCAD has an interface
compatible with ngspice, but I found that the work of using it was a lot
more bother than it was worth to me. I tried also programming directly
in ngspice but as you can imagine that wasn't very practical.

There is an interesting program called Xcos which I wanted to play
around with, but I was having a lot of trouble getting the Javascript to
build on my system — required for the gfx interface. I suppose I might
pursue that further at some point, but I do not feel much motivation at
present.

There is another program called pydda, for setting up numerical
simulation of differential equation systems, which I played around with.
Unfortunately, however, it is not maintained anymore and need some more
features. I'm not much interested in digital programming these days and
even less so in python. Been casually looking into some other things on
occasion, like Julia's differential equation libraries.

-- 
Christopher Howard

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one potentiometer dividing multiple signals Christopher Howard <christopher@librehacker.com> - 2026-03-16 07:21 -0800
  Re: one potentiometer dividing multiple signals Martin Brown <'''newspam'''@nonad.co.uk> - 2026-03-16 15:45 +0000
  Re: one potentiometer dividing multiple signals "Edward Rawde" <invalid@invalid.invalid> - 2026-03-16 11:50 -0400
  Re: one potentiometer dividing multiple signals john larkin <jl@glen--canyon.com> - 2026-03-16 09:42 -0700
  Re: one potentiometer dividing multiple signals Don Y <blockedofcourse@foo.invalid> - 2026-03-16 09:54 -0700
  Re: one potentiometer dividing multiple signals liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-03-16 20:03 +0000
    Re: one potentiometer dividing multiple signals liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-03-19 10:01 +0000
  Re: one potentiometer dividing multiple signals antispam@fricas.org (Waldek Hebisch) - 2026-03-17 21:28 +0000
    Re: one potentiometer dividing multiple signals Christopher Howard <christopher@librehacker.com> - 2026-03-18 08:25 -0800
      Re: one potentiometer dividing multiple signals John R Walliker <jrwalliker@gmail.com> - 2026-03-18 16:34 +0000
      Re: one potentiometer dividing multiple signals Martin Brown <'''newspam'''@nonad.co.uk> - 2026-03-19 12:42 +0000
        Re: one potentiometer dividing multiple signals Christopher Howard <christopher@librehacker.com> - 2026-03-19 11:51 -0800
          Re: one potentiometer dividing multiple signals john larkin <jl@glen--canyon.com> - 2026-03-19 13:16 -0700
          Re: one potentiometer dividing multiple signals liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-03-19 22:18 +0000
          Re: one potentiometer dividing multiple signals Jasen Betts <usenet@revmaps.no-ip.org> - 2026-03-20 07:29 +0000
          Re: one potentiometer dividing multiple signals liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-03-20 09:05 +0000
      Re: one potentiometer dividing multiple signals Jasen Betts <usenet@revmaps.no-ip.org> - 2026-03-20 07:25 +0000
        Re: one potentiometer dividing multiple signals liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-03-20 09:05 +0000
  Re: one potentiometer dividing multiple signals someone <cffbf4deb9142bce48974efc0e64dede@example.com> - 2026-03-17 22:30 +0000
  Re: one potentiometer dividing multiple signals liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-03-19 18:44 +0000
  Re: one potentiometer dividing multiple signals Jasen Betts <usenet@revmaps.no-ip.org> - 2026-03-20 07:12 +0000
  Re: one potentiometer dividing multiple signals john larkin <jl@glen--canyon.com> - 2026-03-20 09:08 -0700
    Re: one potentiometer dividing multiple signals Ross Finlayson <ross.a.finlayson@gmail.com> - 2026-03-20 11:52 -0700
    Re: one potentiometer dividing multiple signals Christopher Howard <christopher@librehacker.com> - 2026-03-23 09:09 -0800
      Re: one potentiometer dividing multiple signals piglet <erichpwagner@hotmail.com> - 2026-03-24 08:48 +0000

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