A `p-n-p` transistor is said to be in active region of operation, When

Options

A. both emitter junction and collector junction are forward biased
B. both emitter junction and collector junction are reverse biased
C. emitter junction is forward biased and collector junction is reverse biased
D. emitter junction is reverse biased and collector junction is forward biased

Answer

To determine when a PNP transistor is in the active region of operation, we need to analyze the biasing of its junctions. Here’s a step-by-step solution:

### Step 1: Understand the Structure of a PNP Transistor
A PNP transistor consists of two p-type semiconductor materials (the emitter and collector) separated by an n-type material (the base). The arrangement is as follows:
- Emitter (P)
- Base (N)
- Collector (P)

### Step 2: Identify the Biasing Conditions
In a PNP transistor, the operation depends on how the junctions are biased:
- The **emitter-base junction** must be **forward biased**.
- The **collector-base junction** must be **reverse biased**.

### Step 3: Define Forward and Reverse Bias
- **Forward Bias**: This occurs when the p-type material (emitter) is connected to a higher potential than the n-type material (base), allowing current to flow easily from the emitter to the base.
- **Reverse Bias**: This occurs when the p-type material (collector) is connected to a lower potential than the n-type material (base), preventing current from flowing easily from the base to the collector.

### Step 4: Conclusion
A PNP transistor is said to be in the active region of operation when:
- The emitter junction is **forward biased** (allowing current to flow from emitter to base).
- The collector junction is **reverse biased** (preventing current from flowing from base to collector).

### Final Answer
Thus, the correct condition for a PNP transistor to be in the active region is that the emitter junction is forward biased and the collector junction is reverse biased.

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