ljy4468
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beta vs ic bjt
Hi all!
In BJT, beta is low at low Ic current,
beta is high at medium Ic,
beta is low again at high Ic.
But I cannot understand 'beta is low again at high Ic'.
In books,
"as Ic increases further, β begins to decrease rapidly. β degradation at high
Ic occurs when the injected minority carrier density into the base approaches the
majority carrier density thereby increasing the majority carrier charge in the base.Hence, the injected carriers effectively increase the base doping, which reduces
the emitter efficiency and β."
Why "thereby increasing the majority carrier charge in the base"?
Hi all!
In BJT, beta is low at low Ic current,
beta is high at medium Ic,
beta is low again at high Ic.
But I cannot understand 'beta is low again at high Ic'.
In books,
"as Ic increases further, β begins to decrease rapidly. β degradation at high
Ic occurs when the injected minority carrier density into the base approaches the
majority carrier density thereby increasing the majority carrier charge in the base.Hence, the injected carriers effectively increase the base doping, which reduces
the emitter efficiency and β."
Why "thereby increasing the majority carrier charge in the base"?