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Help With Potentiometers

Discussion in 'General Electronics Discussion' started by AddictedNoob, Jul 25, 2016.

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  1. AddictedNoob

    AddictedNoob

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    Jul 25, 2016
    I've recently bought a bunch of potentiometers and have found they are very easy to burn out (even with only a small motor). My potentiometers are rated for 0.2w and I'm trying to pump about 12v and 1a through them so this is understandable. But what I don't understand is how people use them in things such as variable power supplies (As the voltage or current knob). How does this work and how can I do this myself?
     
  2. donkey

    donkey

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    Feb 26, 2011
    ok if you are controlling a motor the ONLY option I would recommend is a PWM module... it looks like a potentiometer(it has one as a part of the circuit) but what it does is vastly different.
    a resistor (potentiometers included) act like a converter.... (really bad analogy here but gives best description) what it does is it takes power and converts it to heat..... as such the power coming out the other side is less...... now we use resistors primarily because we can identify the amount of power coming out and use it to our advantage
    now PWM does something different, it controls power through an ON/OFF cycle. so it turns something on and off at such a fast rate that we can't tell without probes and fun stuff. the amount of time on compared to off depends on the speed. this will give it a faster or slower speed
     
  3. AddictedNoob

    AddictedNoob

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    Jul 25, 2016
    But what if I want to control some LEDs? And just as an example, what if they were drawing more current than the potentiometer could handle (I'm assuming you can't use a pwm module with LEDs but correct me if I'm wrong)
     
  4. donkey

    donkey

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    Feb 26, 2011
    Pwm works very well with leds too
     
  5. AddictedNoob

    AddictedNoob

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    Jul 25, 2016
    So where would I get something like this and how do I use it? I've heard that you can use arduinios, but I'm in the market for something cheaper if that's possible.
     
  6. davenn

    davenn Moderator

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    Sep 5, 2009
    zillion of them on ebay search for PWM motor driver and PWM LED driver
     
  7. donkey

    donkey

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    Feb 26, 2011
    to use them simply plug them in... where it says v in + and - connect power supply
    where it says v out +- connect item....... not that hard and easy to use
     
  8. BobK

    BobK

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    Jan 5, 2010
    Potentiometers are not for controlling power directly. In a PWM controller they provide a variable voltage that controls the percentage of time the power is on. The current to run the motor or LEDs does not go through the potentiometer.

    Why? It would heat up and burn out if you did that :D

    Bob
     
    hevans1944 and Merlin3189 like this.
  9. oyvdahl

    oyvdahl

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    Oct 11, 2012
    If you don't want to complicate things with the PWM route, you can also use the potentiometer to control the current going through a transistor.
     
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