Answer to Question #162735 in Electric Circuits for Hendrix Lagasca

Question

What are the barrier potentials for the base-emitter (BE) and

collector-base (CB) junctions in a silicon transistor?

Answer 1

The diffusion of electrons from both n regions into the p-type base causes a barrier potential,

$V_B$, for both p-n junctions

because in active mode base-emitter junction is forward biased so, to overcome the barrier potential we have to provide voltage > 0.6v.

For a transistor to function properly as an amplifier, the emitter-base junction must be forward-biased and the collector-base junction must be reverse-biased.

The common connection for the voltage sources is at the base lead of the transistor.

The emitter-base supply voltage is designated VEE and the collector-base supply voltage is designated VCC.

For silicon, the barrier potential for both EB and CB junctions equals 0.7 V