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: I just installed a new HP Photo Smart printer and now when I run Micro-Cap I get the error message, "IO Error on LPT1". Everything was working fine before. What is wrong now?

Answer: The Photo Smart printer is a bidirectional type. That means it both reads and writes to the parallel (LPT1) bus. The Micro-Cap 6 Hasp key also is bidirectional and the two are not sharing the bus successfully. Here is a way to minimize the conflict. Assuming the Micro-Cap 6 CD is in the drive, click on the Windows Start menu, select the Run item, browse to the CD drive, and type in this:

hinstall -r -kp -alldrv

Then type in this:

hinstall -i -cnt=yes

This should remove the bus contention and get rid of the error.

Question: I want to create a new model name, different from those already in the model list that is displayed in the Attribute dialog box. How can I do this?

Answer: When the Attribute dialog box (ADB) comes up, just type in the new model name. The ADB model parameter editor will pop-up allowing you to type in the parameters for the new model. When you are finished, click OK and Micro-Cap 6 will place a model statement with your newly entered parameters in the text area of the circuit. The new model name will also appear in the model list box the next time you place another part of this type.

Question: I just got Micro-Cap 6 and I need to read some old Micro-Cap III circuit files. How do I go about converting the Micro-Cap III files to a format Micro-Cap 6 can read?

Answer: Micro-Cap 6 can read Micro-Cap IV and Micro-Cap V files, but Micro-Cap III files must be converted to Micro-Cap IV format first. To do that you must use the CONVERT program. To obtain a copy of that program email your request to Spectrum at and we will email a copy to you.

CONVERT.EXE runs under MSDOS and has a command syntax that can be seen simply by typing "CONVERT" at the MSDOS prompt.

Question: I need a voltage source that is a time-domain function of both current through an inductor and voltage across a resistor. Is there a simple way to make one of these?

Answer: Yes, the NFV source (Component menu / Analog Primitives/ Function Sources) is just what you need. Simply type in the expression you want in the VALUE attribute. Here is a sample VALUE expression similar to the one you might need.

1E-3*I(L2) + 2E-3*V(R10)

This says the instantaneous time-varying voltage across the NFV source is to be calculated as 1E-3 times L2's time-varying current added to 2E-3 times R10's time-varying voltage drop

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