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Examoogle • User • info@examoogle.com • EE-2024-8821
Chapter 1 of 12 • Page 1 of 248🔒 Protected PDF • Watermarked
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A transistor has _____.
One pn junction
Two pn junctions
Three pn junctions
Four pn junctions
Two pn junctions
A Bipolar Junction Transistor (BJT) is a three-terminal semiconductor device characterized by the presence of two p-n junctions formed between three doped regions: the Emitter, Base, and Collector. These junctions are responsible for controlling the flow of charge carriers.
A Bipolar Junction Transistor (BJT) is a three-terminal semiconductor device characterized by the presence of two p-n junctions formed between three doped regions: the Emitter, Base, and Collector. These junctions are responsible for controlling the flow of charge carriers.
IE=IB+IC — Current relationship in a BJT where current is conserved
β=IBIC — Common-emitter current gain definition
In an NPN transistor, for example, the two p-n junctions are formed at the Emitter-Base (EB) interface and the Collector-Base (CB) interface. When the EB junction is forward-biased, electrons are injected into the base, and when the CB junction is reverse-biased, these carriers are swept across the collector, allowing the base current to control the much larger collector current.
A BJT consists of three semiconductor layers (NPN or PNP).
The two junctions are the Emitter-Base (EB) junction and the Collector-Base (CB) junction.
Bipolar refers to the use of both electrons and holes as charge carriers.
High current gain
High transconductance
Low output impedance
Sensitive to temperature variations
Higher power consumption compared to MOSFETs
Limited switching speed at very high frequencies
Amplification of electronic signals
Electronic switching in digital circuits
Oscillators and signal generation
Diode has one pn junction.
BJT has two pn junctions.
A Thyristor (SCR) contains three pn junctions.
B is correct — A transistor (BJT) is constructed with three layers of doped semiconductor material, which inherently results in two back-to-back p-n junctions.
Always remember: Diode = 1 junction, Transistor (BJT) = 2 junctions, Thyristor (SCR) = 3 junctions.