ELEC 226, Spring 2003
Prof. Rich Kozick
Finding the Step Response
- Analyze the circuit at t=0-:
Find the capacitor voltage / inductor current.
- Analyze the circuit at t=0+:
The capacitor voltage / inductor current is the same as at
- For the desired voltages / currents in the circuit:
- Find the "initial value" at t=0+.
- Find the "final value" as t -> infinity.
(This is sometimes easier to find from the Thevenin equivalent circuit.)
- Find the time constant, Leq/RTh or
Ceq * RTh:
- Find the equivalent capacitance / inductance
(if more than one capacitor / inductor).
- Find the Thevenin resistance, RTh, at the terminals
of the capacitor / indictor.
- Use the
general formula for step response.