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some advice would be great

Discussion in 'General Electronics Discussion' started by curlz, Oct 17, 2014.

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  1. curlz

    curlz

    2
    1
    Oct 17, 2014
    would i be able to use a standard (100/200 ohm) adjustable potentiometer to alter the speed of a 12v dc fan or would i need some sort of voltage regulator and resistors to "help" it out

    thanks for any advice
     
    Last edited: Oct 17, 2014
  2. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

    8,393
    1,271
    Nov 28, 2011
    You need something to boost the current capability of the potentiometer. There are several options, many of which are nicely presented and described at this page:

    http://www.pcsilencioso.com/cpemma/ef.html

    Those options are all "linear" regulators - a transistor conducts more or less, to adjust the output voltage. This forces the pass transistor to dissipate power, which means it needs a heatsink. Usually, power dissipation is worst when the fan is running at about half of the supply voltage. If the fan draws more than a few watts, it may be worthwhile using PWM (pulse width modulation) to avoid the heat dissipation.
     
    hevans1944 likes this.
  3. curlz

    curlz

    2
    1
    Oct 17, 2014
    thanks alot. i wasn't really expecting such a quick and informative response.
    i will have a look through the link.

    thanks again
     
    KrisBlueNZ likes this.
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