Re: BJT transistor beta, vs Ebers-Moll, Gummel-Poon, and the other tools God has given us

From: Paul Burridge (pb_at_notthisbit.osiris1.co.uk)
Date: 12/11/04 

Date: Sat, 11 Dec 2004 16:36:46 +0000

On Tue, 07 Dec 2004 20:17:44 -0500, John Popelish <jpopelish@rica.net>
wrote:

>Ohm's law applies only to things that hold a constant (or reasonably
>nearly so) ratio of voltage to current over some range of voltage and
>current. Just dividing an arbitrary voltage drop caused by an unknown
>process by the current passing through that process does not define
>the process resistance if that ratio is not predictive of the voltage
>at a different current or vice versa. Processes that have non
>constant ratios of voltage drop to current are called non ohmic for a
>reason. And that reason is that ohm's law does not apply to them.

Surely it does *sort-of* apply; only exponentially rather than
linearly in the case of a p-n junction. Problem being Ohm's law is
entirely linear! :-| 

-- 
"What is now proved was once only imagin'd." - William Blake, 1793.

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