Problem 10.7 - RC Circuit Response as a Function of Initial Voltage
*
* The circuit for this problem is from textbook Chap. 10, Problem 34.
*
* NOTE: This is a three-part problem.
* 1. Write a PSpice program using the SIN function and .TRAN analysis
* to solve for the time-dependent voltage across the capacitance.
* Observe the start-up transient in the voltage on a PROBE graph.
* 2. Using hand-calculation and voltage division, determine the phasor
* (complex) capacitance voltage. Write the expression for the time
* domain capacitance voltage, vc(t). From this equation, determine
* the t=0 capacitance voltage, vc(0).
* Using vc(0) as the initial condition on the capacitance, re-run
* the analysis of Part 1. Observe the capacitance voltage on a
* PROBE graph. Is there a start-up transient in this case? Why?
* 3. CHALLENGE PROBLEM! Assume that the capacitance voltage has the
* same amplitude as in Part 2, but change the angle to -90ø. Using
* this new expression for the capacitance voltage, solve for the
* new source voltage. Re-run Part 1 with the new source voltage
* angle. Display the capacitance voltage on a PROBE graph. Is there
* a start-up transient in this case? Why, or why not?
*
.OPT NOPAGE NOBIAS ; Use this statement for Versions 4.03 or
; later. For earlier versions delete NOBIAS.
VS1 1 0 SIN(0 10 ??????? 0 0 ???) ; Complete the statement.
R1 1 2 1000
C1 2 0 1U
.TRAN ????????????????????????? ; Complete the .TRAN command. Use a
; final time equal to four periods
; at the sinusoidal source frequency.
.PROBE
; Use .PRINT or .PLOT commands as desired.
.END
Problem 10.7, Part 2. RC Circuit Response as a Function of Initial Voltage
*
* Hand-calculate the initial capacitance voltage.
* Re-run Part 1 with the new initial condition. Observe the output
* waveform. Is there a start-up transient in this case?
*
.OPT NOPAGE NOBIAS ; Use this statement for Versions 4.03 or
; later. For earlier versions delete NOBIAS.
VS1 1 0 SIN(0 10 ??????? 0 0 ???) ; Complete the statement.
R1 1 2 1000
C1 2 0 1U IC=??? ; Enter the initial (t=0) voltage.
.TRAN ??????????????????????????? ; Complete the .TRAN command. Use a
; final time equal to four periods
; at the sinusoidal source frequency.
.PROBE
; Use .PRINT or .PLOT commands as desired.
.END
Problem 10.7, Part 3. RC Circuit Response as a Function of Initial Voltage
*
* Assuming that the capacitance voltage has a -90ø angle, find
* the expression for the new source voltage (only the angle changes).
* Since Cos(-90ø)=0, there is no initial voltage in this case. Re-run
* Part 1 with the new source voltage. Display the output waveform on
* a PROBE graph. Is there a start-up transient in this case? Why?
*
.OPT NOPAGE NOBIAS ; Use this statement for Version 4.03 or later.
; For earlier versions, delete the NOBIAS term.
VS1 1 0 SIN(0 10 ??????? 0 0 ???) ; Complete the statement.
R1 1 2 1000
C1 2 0 1U
.TRAN ??????????????????????????? ; Complete the .TRAN command. Use a
; final time equal to four periods
; at the sinusoidal source frequency.
.PROBE
; Use .PRINT or .PLOT commands as desired.
.END