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Scaling linear DC voltage to non linear
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Scaling linear DC voltage to non linear

by shobley on Tue Aug 25, 2009 9:33 am

Does anyone know if it's possible to create an analog circuit that can take an input voltage 0-5v and scale it in a non linear fashion - more like a 0-5v curve?

I can do this with a microcontroller and a lookup table, but I was wondering if there was non mpu solution. Ideally it would provide a couple of pots to "twiddle" with the output curve.

I'm trying to make a linear response theremin, and the pitch CV is currently non-linear, and not-very-easy-to-play(tm)*

I would like to keep the whole thing in the analog domain if possible.

Steve


* Used under license from the Theremin Marketing Board.
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Re: Scaling linear DC voltage to non linear

by zener on Tue Aug 25, 2009 1:19 pm

Before there were digital computers there were analog computers. So they had all kinds of circuits for making logs, powers etc. I would think you could find an op-amp circuit to do this. Search around a bit.

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Re: Scaling linear DC voltage to non linear

by shobley on Tue Aug 25, 2009 3:38 pm

Thanks, I just needed to know what to look for.

I found the log / antilog functions, and something that looks like it might be exponential.

I think the best fit would be an antilog.
http://www.stephenhobley.com
http://www.youtube.com/shobley
For all your laser harp, tesla coil, and killer robots from outer space needs.
shobley
 
Posts: 184
Joined: Fri Sep 07, 2007 5:16 pm

Please be positive and constructive with your questions and comments.