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Time Constants of RL circuits

  1. Aug 7, 2011 #1
    Hello, I am currently studying RL circuits and I know that when an inductor is attached to a resistor of large value, the time for the energy stored in the inductor to dissipate in the resistor is shorter and vice versa.

    This is proven mathematically by the time constant term Tau : L/R

    But how does this happen physically?

    It's a little counter intuitive for me since, I would think that a smaller resistance would allow energy to "flow" faster and vice versa.

    Thank you.
  2. jcsd
  3. Aug 7, 2011 #2
    The higher resistance converts the electrical energy into heat, so the circuit will slowly lose energy. The higher the resistance the quicker that energy is covered into heat.

    If I am not mistaking, is tau is low (R >> L), then the dissipation of energy is almost instantaneous. However, if tau is large (L >> R), then the current will flow for quite a bit longer.

    I hope that answers your question :)
  4. Aug 7, 2011 #3
    Thank you khemist.
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