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News:

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.

 

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Easily Overlooked Features - Spring 2004

 

This section is designed to highlight one or two features per issue that may be overlooked because they are not made visually obvious with a toolbar button.

TMAX, TMIN, FMAX, FMIN Analysis Variables
There are four variables available in Micro-Cap that reference the range of the simulation for either transient or AC analysis. These variables are defined as follows:

TMIN - Starting transient analysis time
TMAX - Ending transient analysis time
FMIN - Starting AC analysis frequency
FMAX - Ending AC analysis frequency

The main use for these variables is to reference them in the X Range expression field in the Analysis Limits dialog box. For example, when the X Range has been defined as:

TMAX, TMIN

for a transient analysis, the X Range will constantly be scaled to the values in the Time Range field. If the Time Range field has been set to 10m, when the simulation is run, TMAX is set to 10m and TMIN is set with the default value of 0. The advantage of this method is that the X Range will automatically update to any changes made in the Time Range field, so there isn't a need to have to manually edit the X Range fields each instance the simulation time is changed. FMAX and FMIN operate in the same manner in AC analysis by deriving their values from the Frequency Range field.

These variables are easily placed in an X Range field for either transient or AC analysis by right clicking in the X Range field when in the Analysis Limits dialog box. A left click on the X Range header will let you place them in for all available waveforms.

These variables are also available for use in the schematic. An NFV function source can have its VALUE attribute defined as:

5*sin(2*PI*(1/TMAX)*t)

This equation will produce a sine wave with an amplitude of 5 whose period will always be equivalent to the maximum time value specified in the Time Range field of the Transient Analysis Limits dialog box.

 
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