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

From: Kevin Aylward (salesEXTRACT_at_anasoft.co.uk)
Date: 12/07/04 

Date: Tue, 07 Dec 2004 08:00:32 GMT

radio913@aol.com wrote:
>> And how does this contradict the view that the bipolar transistor is
> voltage *controlled* which has the nuisance of dealing with the
> *effect*
>> of base current?
>
>> Why does it not sink in that there are effects and causes to effects?
>> Vbe is a cause, base current is an effect.
>
>
> Why doesn't it sink in that i don't disagree with you
> on this point? Maybe you should write a "paper"
> on the fact that a voltage induces a current.
>
> You can still consider it a CCCS.

But irrelevant to the issue at hand. To wit, the transistor is a voltage
controlled device. Sure, we can always transform models, but this don't
transform reality.

>
>
>>> ALL of the industry uses Beta to describe a
>>> BJT in the data sheets, and NEVER transconductance.
>
>> This has already been explained. Transconductance is the same for all
>> transistor, so why state it?
>
> Bull***! Gm is the same for all transistors?

Essentially, yes.

>
> It's not even the same for a single transistor, let
> alone many of them!
>

We are discussing the first order approximation, as such gm is
essentially, the same. Its gm=40.Ic at standard temperature.

Sure, there is an internal Re, but over a large current range, the
effect of this is minimal. If we include it, it still don't change the
voltage controlled nature of the device.

Kevin Aylward
salesEXTRACT@anasoft.co.uk
http://www.anasoft.co.uk
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