Describe the basic principle of operation of a bipolar junction transistor. Include explanation for the following: i. When minority carriers flow across the transistor ii. why the collector current is almost unaffected by the collector potential
Describe the basic principle of operation of a bipolar junction transistor. Include
explanation for the following:
i. When minority carriers flow across the transistor
ii. why the collector current is almost unaffected by the collector potential
(i)
In a bipolar junction transistor base is lightly doped and width of base region is small.
For npn transistor, Emitter and collector are n type material whose minority carriers are holes. For Active mode transistor B-E junction are forward biased and C-B junction are reversed biased.
Due to reverse biased C-B junction and lightly doped base region depletion region are more penetrated in base region compared to other region.
Due to forward biased B-E junction, holes from base to emitter and electron from emitter to base starts moving and causes flow of current. Due to minority carrier flow from each region diffusion current starts flowing.
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