The name Bipolar in BJT signifies:
The name Bipolar in BJT signifies: Correct Answer current flow is due to transport of both electrons and holes
BJT stands for Bipolar junction transistor
- B = Bipolar (because conduction is due to two opposite type of carriers Holes and electrons)
- J = Junction refers to the two PN junctions between emitter and base, and collector and base.
- BJT's are current-driven devices.
- The current through the two terminals is controlled by a current at the third terminal (base).
- It is a bipolar device (current conduction by both types of carriers, i.e. majority and minority electrons and holes)
- It has a low input impedance.
The arrow on the symbol for bipolar transistors indicates the PN junction between base and emitter and points in the direction in which conventional current travels, i.e. the direction of holes.
NPN:
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When the emitter-base is forward biased, holes from the base (p-type) start to flow to the emitter side (n-type) and electrons start to flow from the emitter to the base. The direction, however, represents the direction of the hole flow.
PNP:
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When the emitter-base junction is forward biased, holes from the emitter starts to flow to the base. The direction of the arrow also indicates the same.