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.ic Line
- General Form:
.ic v(nodname)=val v(nodname)=val ...
- Example:
.ic v(11)=5 v(4)=-5 v(2)=2.2
This line is for setting transient initial conditions. It has two
different interpretations, depending on whether the uic
parameter is specified on the .tran line. Also, one should not
confuse this line with the .nodeset line. The .nodeset
line is only to help dc convergence, and does not affect final bias
solution (except for multi-stable circuits). The two interpretations
of this line are as follows:
- When the uic parameter is specified on the .tran line,
then the node voltages specified on the .ic line are used to
compute the capacitor, diode, BJT, JFET, and MOSFET initial
conditions. This is equivalent to specifying the ic=... parameter on each device line, but is much more convenient.
The ic=... parameter can still be specified and will take
precedence over the .ic values. Since no dc bias (initial
transient) solution is computed before the transient analysis, one
should take care to specify all dc source voltages on the .ic
line if they are to be used to compute device initial conditions.
- When the uic parameter is not specified on the .tran
line, the dc bias (initial transient) solution will be computed
before the transient analysis. In this case, the node voltages
specified on the .ic line will be forced to the desired initial
values during the bias solution. During transient analysis, the
constraint on these node voltages is removed.
Next: .nodeset Line
Up: Initialization
Previous: .global Line
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Stephen R. Whiteley
2012-09-24