# How to calculate impedance given volatge and current waveforms

Discussion in 'Homework Help' started by anony, Apr 4, 2010.

1. ### anony Thread Starter New Member

Apr 3, 2010
12
0
i have a problem. I want to calculate the impedance of the system . The information i have of the system is its voltage response when a pulse of curent is applied . i have attached the volatge and current waveform in figure. please help me to find teh impedance of the system with these waveforms
ps. green is current and puple is voltage waves
thanks

Last edited: Apr 10, 2010
2. ### Ghar Active Member

Mar 8, 2010
655
72
From the look of it you have a resistor in series with a capacitor.

For a flat current pulse remember that voltage of a capacitor is t*I/C.
For a resistor of course it's just IR.

Initially the voltage on the capacitor is zero, so the very first point of voltage is just resistive. Once your current is 0 again the voltage across the resistor is zero so that non-zero voltage at the end is what the capacitor is holding.

3. ### anony Thread Starter New Member

Apr 3, 2010
12
0
thankyou so much. This seems to solve my problem. but i have to make sure with taking more readings. any way thank you. its really a great help