A working transistor 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 `P` or `Q` some resistance is seen on the multimeter . Which of the following is true for the transistor ?

Options

A. Option1 It is an npn transistor with R as base
B. Option2 It is a pnp transistor with R as collector
C. Option3 It is a pnp transistor with R as emitter
D. Option4 It is an npn transistor with R as collector

Answer

To solve the problem, we need to analyze the given information about the transistor and the results from the multimeter tests.

### Step-by-Step Solution:

1. **Identify the Configuration of the Transistor**:
- A transistor has three terminals: Emitter (E), Base (B), and Collector (C). The terminals are labeled as P, Q, and R. We need to determine which terminal corresponds to which part of the transistor.

2. **Analyze the First Test Result**:
- The first test indicates that there is no conduction between P and Q when the common (negative) terminal of the multimeter is connected to R. This suggests that P and Q cannot be the Emitter and Collector because, in a functioning transistor, there should be some conduction between these two terminals when the Base is properly biased.

3. **Determine the Role of Terminal R**:
- Since there is no conduction between P and Q, it implies that one of these terminals must be the Base. Given that R is connected to the negative terminal and shows no conduction with P and Q, we can conclude that R is likely the Base terminal.

4. **Analyze the Second Test Result**:
- In the second test, when the common terminal of the multimeter is connected to R (Base) and the positive terminal is connected to either P or Q, some resistance is observed. This indicates that the transistor is in reverse bias.

5. **Identify the Type of Transistor**:
- In a reverse-biased configuration, if the Base (R) is connected to the negative terminal and the Emitter (either P or Q) is connected to the positive terminal, it suggests that the transistor is an NPN type. In an NPN transistor, the Base is more negative than the Emitter, allowing for reverse bias.

6. **Conclusion**:
- Based on the above analysis, we can conclude that the transistor is an NPN type with R as the Base terminal.

### Final Answer:
The transistor is an NPN type with R as the Base.

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