Voltage controlled potentiometer?

Discussion in 'The Projects Forum' started by wayneh, Oct 2, 2012.

  1. wayneh

    Thread Starter Expert

    Sep 9, 2010
    12,094
    3,033
    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?
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,646
    2,345
  3. wayneh

    Thread Starter Expert

    Sep 9, 2010
    12,094
    3,033
  4. wayneh

    Thread Starter Expert

    Sep 9, 2010
    12,094
    3,033
    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.

    [​IMG]
     
  5. RamaD

    Active Member

    Dec 4, 2009
    254
    33
    Found an old circuit using JFETs. Will this be of use, with a potential divider to control?

    VCA.gif
     
    Last edited: Oct 3, 2012
  6. wayneh

    Thread Starter Expert

    Sep 9, 2010
    12,094
    3,033
    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.
     
Loading...