Voltage Sources

Spice Syntax

VXXXXXXX N+ N- <DC >DC/TRAN Value> <AC <AC Mag < AC Phase>>>


Additional Information

More details can be found in the HyperSpice chapter in Extended Definitions for Advanced Users and Spice for Activate Users.


VCC 10 0 DC 6 

VIN 13 2 0.001 AC 1 SIN(0 1 1MEG) 

VIN 2 0 PWL 0 0 10n 0 11n 3.3 25n 3.3 26n 0 R

N+ and N- are the positive and negative nodes, respectively. Note that voltage sources need not be grounded.

Voltage sources, being used for circuit excitation, are the 'ammeters' for SPICE, that is, zero valued voltage sources may be inserted into the circuit for the purpose of measuring current. They of course have no effect on circuit operation since they represent short-circuits.

DC/TRAN is the dc and transient analysis value of the source. If the source value is zero both for dc and transient analyses, this value may be omitted. If the source value is time-invariant (e.g., a power supply), then the value may optionally be preceded by the letters DC.

ACMAG is the AC magnitude and ACPHASE is the AC phase. The source is set to this value in the AC analysis.

If ACMAG is omitted following the keyword AC, a value of unity is assumed.

If ACPHASE is omitted, a value of zero is assumed.

If the source is not an ac small-signal input, the keyword AC and the ac values are omitted. Any independent source can be assigned a time-dependent value for transient analysis.

If a source is assigned a time-dependent value, the time-zero value is used for DC analysis.