Problem 7.5 - A Pulse with Exponentially Shaped Rise and Fall
*
* NOTE: This is a two-part problem.
* Part 1: Use the EXP function to generate a waveform with zero value
* from t=0 to t=1 second, then rising exponentially to t=3 seconds
* with a time constant of 1 second. At t=3 seconds the waveform is
* to fall back to zero with a time constant of 2 seconds.
* Use the .TRAN command with a time interval 0 < t < 10 seconds.
* Use .PROBE to display a graph of the voltage V(1).
*
* Part 2: CHALLENGE PROBLEM! Write the mathematical expression for a
* rising exponential waveform that goes through zero at t=1 second,
* has a time constant of 1 second, and a final value of 5 volts.
* Note: The expression has the mathematical form 5-K*EXP(-TIME) so
* that it can be plotted on a PROBE graph versus the horizontal
* axis variable TIME. Solve for K.
* Re-draw the graph for the solution of Part 1 of this problem. Add
* your calculated expression to the graph of V(1).
* This expression will start at a large negative value at t=0. You
* can select "Y_axis" on the PROBE menu and then "Set_range." Set
* the range to 0,6 to cut off the bottom of the waveform. The
* positive part of the waveform will coincide with the rising part
* of the exponential waveform generated in Part 1.
*
.OPT NOPAGE
V1 1 0 EXP(0 ??? ??? ??? ??? ???) ; Enter the correct values
; for the parameters of the
; exponential waveform.
R1 1 2 1K
R2 2 0 3K
.TRAN ??? ??? ??? ??? UIC ; Enter values for the .TRAN command
; for a 15 second analysis period
; and a maximum time step to give a
; minimum of 100 data points for a
; PROBE graph of the waveform.
.PROBE
.END