A working transitor with its three legs marked `P, Q and R` is tested using a multimeter No conduction is found between `P, Q `by connecting the common (negative) terminal of the multimeter to `R`and the other (positive) terminal to or `Q` some resistance is seen on the multimeter . Which of the following is true for the transistor ?

Options

A. It is an npn transistor with R as base
B. It is an pnp transistor with R as collector
C. It is an pnp transistor with R as emitter
D. It is an npn transistor with R as collector

Answer

A

Explanation

When a multimeter is connected between `P` and `Q` and there is no conduction between `P` and `Q`, then `P` and `Q` are of same type of semiconductors, i.e. either both are of n-type or p-type. It means that emitter and collector of a transistor are `P` and `Q`. When R is connected to negative terminal of multimeter and positive terminal to `P` and `Q`, then emitter-base junction will conduct to some extent due to reverse biasing. The similar is the case of collector-base junction. Thus, the transistor is npn transistor with `R` as base.