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12v reverse speed control circuit diagram

  1. Jul 5, 2009 #1

    I have a 9v motor (can run to 24v). I need to control the speed of the motor and reverse the direction. I also wanted to control it with a duel-potentiometer, but i cant seem to find any way to do this. can someone help with a circuit diagram please?
    (This is my first time building a circuit so any help you can offer please)

  2. jcsd
  3. Jul 5, 2009 #2


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    This shows a circuit that looks like what you need.

    http://www.dprg.org/tutorials/2005-11a/index.html [Broken]

    Note that the output is taken from pin 7 which is unusual but OK in this circuit. Pin 3 is normally the output of a 555.
    That would give you variable speed and you would need a Double pole double throw switch to change the polarity of the voltage getting to the motor to reverse its direction.


    The motor would be on the right and the input voltage on the left in this diagram.
    Last edited by a moderator: May 4, 2017
  4. Jul 5, 2009 #3
    This National Semiconductor LMD-18200 full H-bridge offers full 3-amp 24-volt forward-reverse pulse width modulation w/braking.You can probably use the PWM to control different motor speeds in forward and reverse. You can also do it with diodes and pots on the output.
    http://acroname.com/robotics/parts/R27-18200.pdf [Broken]
    Tell us more about the motor rating.
    Last edited by a moderator: May 4, 2017
  5. Jul 6, 2009 #4
    Thanks for the help.
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