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Capacitor control

  1. Sep 23, 2007 #1
    I'm curious to know if there is any way of controlling the amount and rate of discharge from a capacitor, can anyone help me out?
  2. jcsd
  3. Sep 23, 2007 #2


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    Staff: Mentor

    Sure. When you discharge a capacitor, the rate of discharge depends on the resistance of what you discharge it through.
  4. Sep 23, 2007 #3
    RC time constant.... C is fixed, R is dependent on your design.
  5. Sep 23, 2007 #4
    I see, so if i wanted to hook up an ultracapacitor or an aerogel capacitor to a couple of resistors in a simple circuit, i could theoretically slow down the rate of discharge? would i be able to run a small electric motor off of this discharge?
  6. Sep 23, 2007 #5


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    Science Advisor
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    Let's see. If the resistance of the motor was about 10 ohms and the capacitor was big, say 6 farad; the time constant (RC) would be 60 seconds.
  7. Sep 23, 2007 #6
    Ok, so what you're saying is in order to increase the amount of time a discharge is happening, i must increase the capacitance and decrease the resistance? When speaking in terms of say, a thousand ultracapacitors within a circuit, would i be able to power a super-efficient electric motor over an extended period of time?
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