 #1
 27
 4
Homework Statement:

A capacitor of variable capacitance is being discharged by a resistance R. It is known that the power dissipated by the resistance at any time t is constant and that the initial capacitance is worth Co. Determine the capacitance of the capacitor at time t.
Answer: C (t) = Co  t/R
Relevant Equations:
 U = RI
Using:
$$i(t)=\frac{U}{R}.e^{\frac{t}{RC}}
As the power is constant, then the current will be constant, so:
t/RC is constant
I don't know how to proceed anymore. I think you should use some derivative, but I'm still very new to that part, so how can I proceed?
$$i(t)=\frac{U}{R}.e^{\frac{t}{RC}}
As the power is constant, then the current will be constant, so:
t/RC is constant
I don't know how to proceed anymore. I think you should use some derivative, but I'm still very new to that part, so how can I proceed?