Re: gEDA-user: Problem with 2N3906 model in gnucap

[gene <carzrgr8@xxxxxxxxxxxxx>]

al davis wrote:
> I assume you are aware that those model parameters need to be 
> taken with a bit of suspicion.  For example, the NPN gives 
> a "Bf" value (forward beta) of 416.4.   For real transistors 
> this parameter varies widely.  Any number from 200 to 500 would 
> be believable, and they do vary this much in production.  Other 
> parameters vary like this too.  I just picked this one because 
> the beta of a transistor is well understood.
>   
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. 

Just curious.

gene


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