ECE 345 Lecture Notes - Lecture 14: Equivalent Circuit, Regions Of Johannesburg
9 Nov 2017
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Bipolar junction transistor (bjt): the bipolar junction transistor is a semiconductor three terminal device that has a small current (base current) that controls a large current (collector current). This device can be very useful in amplification applications as well as switching applications. An n-p-n bjt and the corresponding circuit symbol. Currents and voltages for the bjt are defined as shown in figure 2 and they follow kirchhoff"s. Notice, for the voltages, the first v v. Be connection constraints such that and subscript corresponds to the + reference mark. i. The p-n junctions form diodes between the base-and-collector and base-and-emitter. The base region is thin such that current from the collector injected into the base flows all the way through the base to the emitter. The current voltage characteristics of the base-emitter and collector-emitter can be viewed separately as shown in figure 3. Region ib ib4 ib3 ib2 ib1 ib6 ib5 ib4 ib3 ib2 ib.
