DC analysis

The .DC command performs a DC sweep analysis on the circuit. The DC sweep analysis calculates the circuit’s bias point over a range of values for sweep variable.

.DC <source> <start> <stop> <step> [<source2> <start2> <stop2> <step2>]



A name of an independent voltage or current source. During the sweep, the source’s voltage or current is set to the sweep value.


Starting value.


Final value.


Incrementing value.


The dc analysis determines the dc operating point of the circuit with inductors shorted and capacitors opened. The dc analysis can be used to generate dc transfer curves: a specified independent voltage or current source is stepped over a user-specified range and the dc output variables are stored for each sequential source value.

For a nested sweep, a second sweep variable, start, end, and increment values can be placed after the first sweep. In the nested sweep the first sweep is the inner loop: the entire first sweep is performed for each value of the second sweep.


.DC VIN 0.25 5.0 0.25
.DC VDS 0 10 .5 VGS 0 5 1
.DC VCE 0 10 .25 IB 0 10U 1U

See also