An n-p-n transistor conducts when [2003]a)both collector and emitter a...
When the collector is positive and emitter is
negative w.r.t. base, it causes the forward
biasing for each junction, which causes
conduction of current.
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An n-p-n transistor conducts when [2003]a)both collector and emitter a...
Understanding N-P-N Transistor Operation
An n-p-n transistor is a type of bipolar junction transistor that consists of two n-type semiconductors (the collector and emitter) separated by a thin layer of p-type semiconductor (the base). For the transistor to conduct, certain conditions must be met regarding the voltages applied to its terminals.
Conducting State Requirements
- The emitter (E) must be at a lower potential than the base (B). This is necessary to allow electrons to flow from the emitter into the base.
- The collector (C) must be at a higher potential than the base. This allows for the collection of electrons that are injected into the base from the emitter.
Explanation of Option C
- In option C, the condition states that the collector is positive and the emitter is negative with respect to the base. This configuration creates the necessary electric field for conduction:
- Collector Positive: This creates a high potential that attracts electrons from the base, enabling the flow of current from collector to emitter.
- Emitter Negative: This allows electrons to flow from the emitter into the base, providing the majority carriers needed for conduction.
Why Other Options Are Incorrect
- Option A: Both negative means no forward bias at the emitter-base junction.
- Option B: Both positive fails to establish the required potential difference for current flow.
- Option D: Having the emitter at the same potential as the base prevents electron injection, thus halting conduction.
In conclusion, for an n-p-n transistor to conduct, the correct configuration is that the collector must be positive and the emitter must be negative with respect to the base, validating option C.