RC CIRCUIT Step and Pulse Response
The RC circuit is shown schematically above with the alternating source
replaced by a steady source.
If a unit step is applied at time zero, then the capacitor voltage is
given by V(C) = 1 - e-t/RC and the resistor voltage
by e-t/RC. This is illustrated by the applet below. The capacitor
voltage is shown in red and the resistor voltage in green. The resistor
voltage also gives an indication of the current in the circuit.
If the voltage after time T is set to zero(s moved from a to b),
then the resulting transient response is shown below.
For 0 £ t £
T the response is Vc = 1 - e-t/CR
For T < t £
¥ the response is
Vc = e-t/CR ´
(eT/CR - 1 )
For t < T , Vc + Vr = 1 and
fot t > T , Vc + Vr = 0.
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COPYRIGHT © 1996 Cuthbert A. Nyack.