BJT transistor model

[edba]

Hi

I have been wondering about creating a behavioral model for a BJT transistor using a sub circuit. The model would cover large signal (DC) and small signal (AC) behavior.

I wondered if anyone knows how to do this. I have thought about using the Ebers-Moll model so DC would be an ideal diode and currect soure (HFE*IB) and AC uses re and (hfe*ib).

I know spice offers the gummel and poon model but think the model is over complicated and takes some of the understanding away, having so many parameters when I only want to model a few. I don't know why it is so complicated as I have known analogue engineers from the 60s, 70s and 80s who don't even uses computers to design their circuits, so believe a more practical approach is better when you get a feel for how the model works,

Br

Edba

[Terry Bites]

Why reinvent the wheel?

[edba]

I want to know whats under the hood i.e. I just want a simplified model that you see in text books, or how do you disable the parameters of the gummel and poon so that it is just like the ebers moll. I know the spice documentation says it simplifies to this but it doesn't say what parameters you need to switch off.