Problem 8.1 - Source-Free Response of an RC Circuit
*
* Calculate "by inspection" the RC time constant of the circuit. To do
* this, reduce the series and parallel combinations of resistances in
* parallel with the capacitance until you have only one resistance and
* one capacitance. The product of the two values is the time constant.
*
* .TRAN command final time to be adjusted to six time constants for
* the PROBE graph display of the source-free response of the circuit.
*
* If you want a printer listing or a printer-plot of the output, the
* .PRINT and/or .PLOT commands should produce 40 output data points.
*
* ===> CHALLENGE PROBLEM! Using the time constant you have calculated,
* write the expression for the voltage across the capacitance. Select
* "Add_Trace" and enter the expression to be plotted by PROBE after
* you have V(1) on the screen. If your expression is correct, the
* two traces will coincide.
*
R1 1 0 10
R12 1 2 10
R2 2 0 5
C1 1 0 ??? IC=??? ; Enter the capacitance value and t=0
; voltage.
.TRAN ??? 9 ??? ??? UIC ; Enter parameters for the .TRAN command.
; TSTEP should be TFINAL/40, and the
; maximum step size should be about
; TFINAL/100. The UIC statement is
; required in order to include the initial
; capacitance voltage in the problem
; solution.
; Add .PRINT or .PLOT commands as desired
; for listed or printer-plot output.
.PROBE
.END