A working transistor with its three legs marked P, Q and R is tested using a m

Question

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

Options:

A . It is an n-p-n transistor with R as collector

B . It is an n-p-n transistor with R as base

C . It is an p-n-p transistor with R as collector

D . It is an p-n-p transistor with R as emitter

E . 35 mA

Answer: Option B
:
B

When a multimeter is connected between P and Q there is no conduction between P and Q, then P and Q are of same type of semiconductor, ie, either both are on n-type or of p-type. It means emitter and collector of a transistor are P and Q. When R is connected to negative terminal of multimeter and positive terminal to P or 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 n-p-n transistor with R as base.

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