jayanth.devarayanadurga
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I have a question regarding BJT.
Fundamentals of Analog Circuits 2nd Edition by Thomas L Floyd and David Buchla
Indian Edition
Page Nos. 131 and 130.
(Heading) Cutoff and Saturation
Para 3
The author says,
Once the base current is high enough to produce saturation, further increase in base current have no effect on the collector current, and the relationship IC = (beta)IB is no longer valid. When VCE reaches its saturation value VCE(sat), which is ideally zero the base collector junction becomes forward biased.
Is it not incorrect. If the (VCE) knee voltage is 0.3 (say) at which the transistor Ic becomes max for a given Ib, then when VCE is between 0 and 0.3V the BE and CB juctions are forward biased and when VCE is 0.3 and less than CB breakdown voltage the BE junction is forward biased and CB junction is reversed biased and the moment VCE becomes 0.3V, Ic reaches Tc(sat) and enters the active region of operation.
Why the author says when Ic is max Ic = (bata)Ib doesn't apply. As per my understanding Ic = (beta)Ib applies in active region op operation and when Ic is max for a given Ib then it is at the edge where it has become saturated and entered active region.
Fundamentals of Analog Circuits 2nd Edition by Thomas L Floyd and David Buchla
Indian Edition
Page Nos. 131 and 130.
(Heading) Cutoff and Saturation
Para 3
The author says,
Once the base current is high enough to produce saturation, further increase in base current have no effect on the collector current, and the relationship IC = (beta)IB is no longer valid. When VCE reaches its saturation value VCE(sat), which is ideally zero the base collector junction becomes forward biased.
Is it not incorrect. If the (VCE) knee voltage is 0.3 (say) at which the transistor Ic becomes max for a given Ib, then when VCE is between 0 and 0.3V the BE and CB juctions are forward biased and when VCE is 0.3 and less than CB breakdown voltage the BE junction is forward biased and CB junction is reversed biased and the moment VCE becomes 0.3V, Ic reaches Tc(sat) and enters the active region of operation.
Why the author says when Ic is max Ic = (bata)Ib doesn't apply. As per my understanding Ic = (beta)Ib applies in active region op operation and when Ic is max for a given Ib then it is at the edge where it has become saturated and entered active region.