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A n-p-n transistor conducts when...

A `n-p-n` transistor conducts when

A

both collector and emitter are positive with respect to the base

B

collector is positive and emitter is negative with respect to the base

C

collector is positive and emitter is at same potential as the base

D

both collector and emitter are negative with respect to the base

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To determine when an n-p-n transistor conducts, we need to understand the biasing conditions of its junctions. An n-p-n transistor consists of three regions: the emitter (n-type), the base (p-type), and the collector (n-type). ### Step-by-Step Solution: 1. **Identify the Junctions**: - An n-p-n transistor has two junctions: the emitter-base junction and the collector-base junction. 2. **Forward Biasing the Emitter-Base Junction**: - For the transistor to conduct, the emitter-base junction must be forward biased. This means that the emitter (n-type) should be at a lower potential than the base (p-type). In practical terms, the emitter should be connected to a negative voltage relative to the base. 3. **Reverse Biasing the Collector-Base Junction**: - Simultaneously, the collector-base junction must be reverse biased. This means that the collector (n-type) should be at a higher potential than the base (p-type). In practical terms, the collector should be connected to a positive voltage relative to the base. 4. **Charge Carrier Movement**: - When the emitter-base junction is forward biased, electrons from the emitter flow into the base. Some of these electrons recombine with holes in the base, but most will continue to the collector. The reverse bias at the collector-base junction helps to attract these electrons into the collector. 5. **Conclusion**: - Therefore, for an n-p-n transistor to conduct, the emitter must be negative with respect to the base (forward bias), and the collector must be positive with respect to the base (reverse bias). ### Final Answer: An n-p-n transistor conducts when the **emitter is negative and the collector is positive with respect to the base**.
To determine when an n-p-n transistor conducts, we need to understand the biasing conditions of its junctions. An n-p-n transistor consists of three regions: the emitter (n-type), the base (p-type), and the collector (n-type). ### Step-by-Step Solution: 1. **Identify the Junctions**: - An n-p-n transistor has two junctions: the emitter-base junction and the collector-base junction. 2. **Forward Biasing the Emitter-Base Junction**: ...
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