Voltage controlled potentiometer?

Thread Starter

wayneh

Joined Sep 9, 2010
17,496
I'm looking for a way to control a potentiometer, or a resistor, or the gain of an op-amp, using a 0-3.3V analog DC control voltage. The resistor needs to behave like a resistor up to frequencies of about 1kHz, but of course more is better.

I've searched a bit and found a few parts that I might use but nothing that really stands out as an obvious choice. Seems like digital control is more common.

Any favorites?
 

Thread Starter

wayneh

Joined Sep 9, 2010
17,496
It looks like what I need is addressed in the TI datasheet. There are similar examples that use capacitive coupling, which wouldn't work for me, but this example is directly coupled.

I can't quite grasp what all is going on in this circuit but it should work for me. If anyone follows this topic, search the forum for LM13700 and you'll find additional information.

 

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RamaD

Joined Dec 4, 2009
328
Found an old circuit using JFETs. Will this be of use, with a potential divider to control?

VCA.gif
 
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Thread Starter

wayneh

Joined Sep 9, 2010
17,496
I found a few JFET based designs. This one looks doable.

If/when I go forward, I'll use the LM13700. It seems there are a lot of folks out there that have experience with it.
 
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