Why the beta of BJT doesn't a constant?

[mpig09]

Hi all:

I sweep ib and get ic, I found the the beta of BJT doesn't a constant?

Does anyone know the reason?

Thanks for your reply.
mpig

 

[erikl]

Re: Why beta of BJT isn't constant?

Leakage current, emitter efficiency, series resistance. Read about BJT theory and operation!

 

[LvW]

If you know
* that beta is Ic/Ib, and
* How resp. why Ib does exist as a (not constant) part of Ie

it will be clear that it cannot be a constant value - independent on Ic and environmental conditions.