Junction Transistor
An n-p-n transistor has three leads A, B and C. Connecting B and C by moist fingers, A to the positive lead of an ammeter, and C to the negative lead of the ammeter, one finds large deflection. Then, A, B and C refer respectively to:
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Answer: (a)
- In the meter used as an ohmmeter, the +ve lead is connected to the negative of the internal cell, so A is at lower potential and C at higher potential.
- Moist fingers join B to C, so the base gets a small current from the higher-potential lead.
- For an npn transistor, a large current flows only when the collector is at high potential, the emitter low, and the base is forward biased with respect to the emitter.
- So A is emitter, B is base and C is collector: answer (a).