In a bipolar junction transistor
[amp_mcq option1=”all the three regions (the emitter, the base and the collector) have equal concentrations of impurity” option2=”the emitter has the least concentration of impurity” option3=”the collector has the least concentration of impurity” option4=”the base has the least concentration of impurity” correct=”option4″]
This question was previously asked in
UPSC CDS-2 – 2016
– These regions are doped with impurities (donors or acceptors) to create n-type and p-type semiconductors.
– The doping levels are designed specifically for the transistor’s operation:
– Emitter: Heavily doped (high concentration) to efficiently inject charge carriers (electrons or holes) into the base.
– Base: Lightly doped (low concentration) and made very thin to allow most injected carriers from the emitter to reach the collector and to minimize recombination within the base.
– Collector: Moderately doped (intermediate concentration, less than emitter but more than base) and typically larger in size to collect the carriers from the base and dissipate heat.