Electronics Fans

Discussion in 'Modding' started by ellism, 14 Sep 2003.

  1. ellism

    ellism What's a Dremel?

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    I want to make a circuit that is a Fan speed controler and speed reading in one and i would like to know exactly what the third wire on the fan does. tnks.
     
    ellism, 14 Sep 2003
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  2. fump

    fump What's a Dremel?

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    the 3rd wire is the rpm monitor. it isnt importent unless you have a fan monitor on yor board.
     
    fump, 14 Sep 2003
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  3. ellism

    ellism What's a Dremel?

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    yes i know that but i want to creat a rpm metor board and i want to know how this wire acts, when it creats pules etc.
     
    ellism, 14 Sep 2003
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  4. fump

    fump What's a Dremel?

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    :search:
     
    fump, 14 Sep 2003
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  5. cpemma

    cpemma Ecky thump

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    Checked a Sunon (KD1208PTB2), behaves like open-collector (fig 3c on the link). Adding a 100k pull-up to 12v gave around 6v sensor reading - I'd have assumed that meant a 50% duty cycle but with no 'scope I won't argue.

    You get 2 pulses per rev, so a 3000rpm fan generates a 100Hz signal, easy to convert back to a DC voltage with an LM2917 .
     
    cpemma, 14 Sep 2003
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