Subelement C: Components— Topic 26: Transistors-2
Question 3-26C6
Element 3 (GROL)When an NPN transistor is operating as a Class A amplifier, the base-emitter junction:
Explanation
For an NPN transistor to operate as a Class A amplifier, it must be biased in its **active region**.
In the active region:
* The **base-emitter (BE) junction** must be **forward biased**. This allows a small base current to flow, which controls a much larger collector current. Think of it as opening a gate for current from the emitter to the collector.
* The **collector-base (CB) junction** must be **reverse biased**. This condition allows the collector to draw electrons from the base, establishing the amplified current flow and providing the necessary voltage drop for amplification.
Therefore, option D correctly describes the biasing conditions for an NPN transistor operating in Class A: the base-emitter junction is forward biased, and the collector-base junction is reverse biased.
Options A and B describe saturation and cutoff, respectively, neither of which allows for linear amplification over the entire input cycle. Option C describes an incorrect or unusual biasing state.
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