As a mini tutorial, I want to show how to make a
bipolar transistor model for when you can't find a
SPICE model. The hybrid model that I’ll describe is
■ FIGURE B.
■ FIGURE A.
valid only under the conditions given here, whereas
the SPICE model will be valid under all conditions. I
chose the 2N3904 because there is a SPICE model for
comparison and I have the datasheet.
The model is shown in Figure A. I chose R4 and
R5 (not part of the model) to give a collector current
around 10 mA, and modeled around that parameter.
R2 and is called
hie on the
Figure B. At Ic=
10 mA, hie =
.5K. The voltage
source, V1, is
set to zero volts
only function is
to measure the
for the current-controlled
You will find
Program in BASIC
64-bit Floating Point
Sin, Cos, Log and more
30k RAM, 64k Flash
Bi-Directional Level Shifter
3.3V to 5V
with code “NUTS”