Homework Statement
Voltage across 0.2-F cap is given by
v(t)=4(1-Є^(-10t)) for t>0
determine expression for the current i(t)
Homework Equations
i(t)=c (dv(t))/dt
The Attempt at a Solution
I'm really not sure were to begin with this problem what is the Є symbol and how do...
Can anyone tell me what formula I would use to find the time constant for a circuit that reaches 85% of its final value 1.86 seconds after the switch is closed.