Physics - Semiconductors Question with Solution | TestHub
An n-p-n transistor can be considered to be equivalent to two diodes connected. The correct figure out of the following is
(a)
(b)
(c)
(d)
Options:
Answer:
Solution:
An n-p-n transistor consists of two n-type semiconductors (emitter and collector) separated by a thin p-type semiconductor (base).
This configuration can be thought of as two p-n junction diodes connected back-to-back.
In a diode symbol, the triangular part represents the p-type region (anode) and the straight line represents the n-type region (cathode).
For an n-p-n transistor:
1. The base is p-type, so it corresponds to the anode of both equivalent diodes.
2. The emitter and collector are n-type, so they correspond to the cathodes.
Therefore, the equivalent circuit must have the anodes (triangles) of both diodes connected together at the base terminal, with their cathodes (lines) connected to the emitter and collector terminals. This means the diodes should point away from the base towards the emitter and collector.
Figure (b) correctly shows this arrangement, where the base is connected to the p-sides of both diodes, representing an n-p-n transistor.
Answer: b
