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Voltage divider circuit and effect on current

  1. Aug 29, 2011 #1
    Hey,
    Im new and this is just a simple question.
    I want to make a voltage divider circuit to power a 3V dc motor using a 9V battery supply. However the motor draws 0.20amps when there is no load. In conjunction with the voltage divider equation V(out) = (R2 * V(in) )/ (R1+R2) , how to ensure that enough current is supplied to the motor? Also I've read that I will need to take into account the resistance of the motor as well! How do I do this and which resistors should I use?

    Thanks alot for your help,
    77jenko
     
  2. jcsd
  3. Aug 29, 2011 #2
    I'm not sure what you mean by "the motor draws .2amps when there is no load."

    If I'm assuming correctly, I believe you want to model the motor as a load requiring 3V and .2 amps. In this case, you would use ohm's law to model the motor as a resistor (V = IR). Once you have this resistance, you could use it as the R2 in your voltage divider equation, and then solve for your R1.
     
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