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--- Basic Resistor Circuit --- NEWBIE ---

Discussion in 'General Electronics Discussion' started by thisismeavp, Nov 29, 2014.

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  1. thisismeavp

    thisismeavp

    2
    0
    Nov 29, 2014
    I have a circuit in which a L239D motor driver drives a pair of simple DC motors. The motor driver can only supply 600mA on each output, and I have a voltage of 3.3v coming from the motor driver. How do I limit the current so it doesn't fry the chip?

    I know a resistor would be the solution: I have tried to use an Ohm's law calculator to find the required resistance, and it told me I would need 5.5 ohms. I rounded this to 5.6 ohms, as this is a standard size. It also tells me that this is a 2W circuit...

    Does this mean I need a 2W+ resistor at 5.6 ohms? I thought this was strange, as the only resistors that I can get my hands on are 0.25W, and I need to go to specialist companies to get the type I need. Please confirm this is right, as I can't afford to waste any money on this build!
     
  2. Frenoy Osburn

    Frenoy Osburn

    64
    24
    Nov 20, 2014
    What do you mean by that? How did you get 3.3V? on which pins?

    What is the max current that your motors draw?
     
  3. thisismeavp

    thisismeavp

    2
    0
    Nov 29, 2014
    Nevermind! My maximum current (for the motors) was 400mA, not the 700mA I thought it was... I was reading the motor current draw for 6V... It turns out it won't fry the chip anyway :D
     
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