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


Question: How do I create a noiseless resistor?

Answer: In the model statement for a resistor, there is a parameter called NM that is a noise multiplier. To edit the NM parameter in a schematic, go to the Attribute dialog box of the resistor. Define the MODEL attribute if it is not already defined. Highlight the MODEL attribute. Once the model name has been defined and the attribute is highlighted, the parameter fields at the bottom of the dialog box will become active and available for editing. NM will be in the list. This parameter multiplies the noise that the resistor produces by its defined value. Setting NM to 0 creates a noiseless resistor.

Question: I just received a circuit from another user and when I go into transient analysis and try to run, I get an error stating that Micro-Cap canít find a .TOP file. How do I resolve this error?

Answer: The .TOP file is created by the State Variables Editor and is used to store the State Variables that initialize the start of the transient simulation. You would need to get this file from the other user, or in the Transient Analysis Limits dialog box, you can change the State Variables option to Zero or Leave. Changing the State Variables option will most likely give you a different simulation result than what the other user intended since you will be beginning the transient simulation at a different initial point. Whenever the State Variables option is set to Read, there must be a corresponding .TOP file present.

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