Spectrum Software
Industrial Strength Simulation




Spectrum Software has released Micro-Cap 11, the eleventh generation of our SPICE circuit simulator.

For users of previous Micro-Cap versions, check out the new features available in the latest version. For those of you who are new to Micro-Cap, take our features tour to see what Micro-Cap has to offer.




Initial Conditions


How do I set an initial current through an inductor?


There are three ways to set a current through an inductor. Let's assume there is a 10mH inductor with its PART attribute defined as L3, and we want to set an initial condition of 1mA across it.

Inductor INDUCTANCE Attribute
The second way is in the INDUCTANCE attribute of an inductor. Define the inductor's INDUCTANCE attribute as:

10m IC=1m

This will place 1mA through the inductor. Note that the inductor does have polarity, so this condition will place 1mA through the inductor going from its plus pin to its minus pin. You can view which pin is which by enabling the Display Pin Names checkbox in the Attribute dialog box. If the polarity is reversed, just rotate the inductor so that the plus pin and the minus pin are swapped, or you can just set the condition to -1m. The inductance must be specified as a constant for the initial condition to work.

.IC Statement
The first way is with a .IC statement. In the text area or the schematic area, type in the statement

.IC I(L3)=1m

State Variables Editor
When you initially enter transient analysis, go to the Transient menu and choose State Variables Editor. Set the inductor current of L3 to 1m. The polarity is the same as when the INDUCTANCE attribute is defined. You can then write these conditions to a file and use the Read option in the State Variables list, or close and use the Leave option in the State Variables list. The State Variables list is available in the Transient Analysis Limits dialog box.

In most cases, the operating point should probably be disabled in the Transient Analysis Limits dialog box to get desired results. If you use the State Variables Editor though, the operating point must be disabled.






AC Analysis
Analysis - General
DC Analysis
Dynamic DC
Initial Conditions
Monte Carlo
Schematic Editor
Transient Analysis