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Super Noob in need of assistance

Discussion in 'General Electronics Discussion' started by azamor2, Jun 29, 2011.

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  1. azamor2

    azamor2

    2
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    Jun 29, 2011
    I have here a little desk fan that runs 3volt DC 500mA, I also have in my posession an old cellphone charger 5.0volt .7A If I rig these up together am i just asking to burn down my house. Im new to all this and i'd rather hear from experience than totally Eff myself over.
    any thoughts will be appreciated. thanks!
     
  2. davenn

    davenn Moderator

    13,650
    1,885
    Sep 5, 2009
    hi there
    welcometo the forums

    The 3V fan would probably run ok off the 5V to some what faster. There is a risk of cooking it. An easy way to make it happier would be to put a couple of 1N4001 diodes in series with the + volts between the power supply and the fan. this would drop the 5V down to ~ 4V and the fan would have a much longer life expectancy :)

    [​IMG]

    cheers
    Dave
     

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  3. azamor2

    azamor2

    2
    0
    Jun 29, 2011
    Super cool because i dont want to buy batteries every 2 days for this tiny fan haha.
    Thank you sir I do appreciate the help, and I'll probably have more questions in the future haha

    oh just thought of another one, if i add a tiny little dimmer type knob? that any good?
     
    Last edited: Jun 29, 2011
  4. davenn

    davenn Moderator

    13,650
    1,885
    Sep 5, 2009
    your welcome :)

    yes it would, as long as it could handle the current being drawn by the fan.
    you try as an experiment a 1k variable resistor and see hiow it goes ... see if it gets warm. If I was going to do that I would use a wirewound one rather than a carbon track type ( the more common)

    cheers
    D

    PS but if you are not interested in any sort speed control, just go with the 2 diodes much easier
     
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