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: What is rubberbanding and how do I use it?

Answer: Rubberbanding is a schematic mode that can be enabled or disabled from the Preferences dialog box on the Option menu. When it is enabled and you drag wires or components, they stay connected to their original nodes. If it is disabled, dragging can, and usually does, disconnect components and wires from other nodes.

Rubberbanding is extremely useful in "dressing up" a poorly drawn schematic. You can improve part spacing, loosen up densely packed circuit areas, and generally improve the readability of your schematic with rubberbanding. Just drag select the circuit fragment that you want to move, then left-click on it and drag it to a new position.

When using rubberbanding to edit a circuit, you often arrive at a point where you need to temporarily disable or re-enable the rubberbanding feature. SHIFT + CTRL + R can be used to rapidly toggle the rubberbanding mode off and on.

Question: What does the "Add DC Path to Ground" on the Preferences dialog box do?

Answer: In order to solve for the DC operating point, it is necessary to have a finite impedance from every node to ground. The necessity for this can easily be seen because a circuit without an impedance to ground has an infinite number of solutions and this poses something of a problem for the simulator. This option avoids the problem by automatically adding a 1/Gmin resistor to any node that is missing the required "path to ground". Usually it is best to disable this option and provide the impedance manually so that you know what node is involved and can better judge how to provide it with a path to ground.

Question: What does the "Floating Nodes Check" on the Preferences dialog box do?

Answer: A floating node is a node to which there is only one part connected. Most SPICE simulators will not run if there are any floating nodes present. The presumption is that there is no point in having only one part connected to the node, so it must be a circuit error. MC6 can simulate circuits containing floating nodes without any problem, so this option is used as a likely error checker.

Question: I'm having trouble using the WMF picture files. Most of the time it works correctly, but occasionally the text I've added to a plot does not scale well when I re-size it in a document. What am I doing wrong?

Answer: Probably nothing. All versions up to 6.1.0 were scaled at the highest resolution in the Y axis only. If you re-sized it in both directions, the text frequently did not scale the same as the plot. As of version 6.1.1 the program has been improved by scaling text in both directions. Version 6.1.1 can be downloaded from our web site anytime after June 19.
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