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.




Questions and Answers - Fall 2009


Question: I have two of the CoreSat components in my schematic. I would like to set the Bsat and N parameters for each of these components individually. The problem is that when I double click on one of them to open the Attribute dialog box and proceed to edit the parameter values in the text field where the subcircuit model is displayed, it changes those parameters for both CoreSat components. How do I set the parameters for just a single instance of the component?

Answer: In the Attribute dialog box, when a subcircuit model is displayed in the text field, that is the model that all instances of the component will use in that schematic. Any edits to the model in that field will change the model for all instances in the schematic. For a subcircuit, any parameters that can be passed through to the model are specified in the Params: section of the .Subckt header. For the CoreSat model, the subcircuit header is as follows:

.subckt coresat L1 L2 110 100 params: Feddy=25k IVSEC=0 Ae=0.000067 lm=0.037
+lg=0 Bsat=350m ur=6000 N=15 Hc=50

The Bsat and N parameters are two of the parameters that can be passed through to the subcircuit. In order to modify these for an individual component, the PARAMS: attribute needs to be used. Double click on the component while in Select model. When the Attribute dialog box comes up, select the PARAMS: attribute. For the value of the attribute, enter a string such as the following:

Bsat=500m N=10

This string will set the Bsat parameter to 500m and the N parameter to 10 for that specific component. The values for the parameters in the subcircuit header are the default values. When the parameter is specified in the PARAMS: attribute, this value will then have the priority for that instance of the component.

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