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Originally Posted by audioguru The base-emitter voltage change with temperature shows almost the same angle when the current is changed. So temperature has little effect on a transistor's Re. |
True. Re changes about 0.3%/°C, deduced from the fact that room temperature is about 300°K. (1/300~0.3%).
I think kT/q is called a voltage because it does have, in fact, the units of Volts.
k=1.3807e-23 Joules/°Kelvin
q=1.602e-19 Coulombs
T=300°Kelvin at room temperature.
kT/q=0.0259
Joules/Coulomb = .0259
Volts at room temperature.
It is not very sensitive to temperature (at room temperature), as you said, but T is the only variable in the equation. Hence the name "thermal voltage".
28th December 2005, 12:29 AM
Linear Mode
