Junction Transistor
A working transistor with its three legs marked and is tested using a multi-meter. No conduction is found between and . By connecting the common (negative) terminal of the multi- meter to and the other (positive) terminal to or some resistance is seen on the multi-meter. Which of the following is true for the transistor?
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Answer: (a)
- No conduction between P and Q, so they are emitter and collector (two back-to-back junctions); R is the base.
- In an analog multimeter the common (−ve) terminal is the positive of the internal cell, so R is at higher potential than P or Q.
- Conduction in this state means both base junctions are forward biased with the base positive, so the base is p-type.
- p-type base means npn transistor with R as base: answer (a).