On Wednesday 06 February 2008, gene wrote: > Beta also varies with collector current, do the simulators > (and these models) account for this behavior? In fact, the > curves for different transistors (beta vs. IC) are so > incredibly different - some flat, some very peaky before > rolling off.
Short answer: Yes. Long answer: It depends on what model you use. In older simulators, models are compiled into the core, so for a user to change them is difficult or impossible. In most high end commercial simulators, and the development version of gnucap, models are not built in, but under complete control of the user. As provided, one BJT model is compiled in, but there is nothing magic about it. There are several models with varying degrees of accuracy and maturity. As it stands now, there are 3 more as plugins. For mosfets, there are 8 different models supplied with the core, and 53 more as plugins. Some of these differ only trivially. Since models are plugins, you can use an old version of a model if you want. There are more that are not currently available, many of which will become available when the Verilog-A model compiler works. Some of these models are extremely accurate and complex. The gnucap project does not develop models, but rather provides a way to use models developed by others as plugins, and provides the tools for developing models including interactive debugging. _______________________________________________ geda-user mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
