Finally, the HBT's I/V characteristics are swept to make certain that the DC part of the model is reasonable, and to determine the base bias
current that provides the proper collector bias current.
With a constant voltage base bias
, a decrease in the turn-on voltage of the emitter junction causes an increase in collector current.
The bias uses a single supply, and a resistive divider provides the appropriate base bias
for the desired 3 mA current.