Problem 13.4 - Transient Response of an RLC Circuit with Variable Damping
*
* The response of an RLC circuit to a step function input is a
* function of the damping ratio of the circuit. To explore this effect
* using PSpice, use a step function input waveform to circuit of
* Problem 13.3, which has an undamped natural frequency = 10 kHz.
*
* Use the variable resistance model and the .TRAN command with a PWL
* source to evaluate the transient response over a 500-microsecond
* period. Use PROBE to display all four waveforms on one graph.
* Observe that the damped frequency of oscillation in transient
* response and the peak overshoot are functions of the Q of the
* circuit.
*
.OPT NOPAGE NOBIAS
V1 1 0 pwl(0 1) ; This function describes a waveform that
; is equal to 1 at t=0 and for all t > 0.
R1 1 2 RVAR 1
L1 2 3 15.916M
C1 3 0 15.916N
.MODEL RVAR RES(R=250)
.TRAN ????? ????? ??? ???? UIC ; Complete the .TRAN command. The UIC
; statement forces an analysis using
; only the initial conditions at t=0.
; This has the effect of overriding the PWL function
; by setting the input equal to 0 at t=0. The
; transient response would not be correct without
; this feature.
.STEP OCT RES RVAR(R) ??? ??? ??? ; Complete the .STEP command.
.PROBE
.END