This introduction comes from the operating
manual for a circuit simulation program called
Electronics Workbench. Using a graphic interface, it
allows the user to draw a circuit schematic and then have
the computer analyze that circuit, displaying the results in
graphic form. It is a very valuable analysis tool, but it
has its shortcomings. For one, it and other graphic programs
like it tend to be unreliable when analyzing complex
circuits, as the translation from picture to computer code
is not quite the exact science we would want it to be (yet).
Secondly, due to its graphics requirements, it tends to need
a significant amount of computational "horsepower" to run,
and a computer operating system that supports graphics.
Thirdly, these graphic programs can be costly.
However, underneath the graphics skin of
Electronics Workbench lies a robust (and free!) program
called SPICE, which analyzes a circuit based on a text-file
description of the circuit's components and connections.
What the user pays for with Electronics Workbench and
other graphic circuit analysis programs is the convenient
"point and click" interface, while SPICE does the actual