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Capacitance vs. Resistance Proof

  1. May 23, 2016 #1
    Can somebody confirm if this is correct? I'm trying to use a wye-delta transformation on capacitors to solve for equivalent capacitance, but to be super-precise, I want to put capacitance in terms of resistance.

    I = C*(dV/dt)
    V = IR, so I = V/R

    V/R = C*(dV/dt)

    (V*dt) = R*C* dV

    Integrate both sides.

    V*t = R*C*V

    t = R*C which means that R = t/C

    That makes sense, since people talk about a time constant, but I just want to be sure.
  2. jcsd
  3. May 24, 2016 #2

    Simon Bridge

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    Science Advisor
    Homework Helper

    You need to specify the circuit ...

    Your integration assumes that V is a constant with time, but your first equation assumes that dV/dt is not zero, therefore V does vary with time. This is a contradiction (unless I=0). Try using lower case for variable voltages and currents.
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