Assertion : Zener diode is used to obtain voltage regulation
Reason : When Zener diode is operated in reverse bias, after a certain voltage (breakdown voltage) the current suddenly increases.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true not but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false
D. If both assertion and reason are false.

Answer

To analyze the given assertion and reason regarding the Zener diode, we can break it down into a step-by-step explanation:

### Step 1: Understanding the Assertion
- **Assertion**: Zener diode is used to obtain voltage regulation.
- **Explanation**: A Zener diode is specifically designed to operate in reverse bias and maintain a constant output voltage, even when the input voltage varies. This makes it an excellent choice for voltage regulation applications.

### Step 2: Understanding the Reason
- **Reason**: When Zener diode is operated in reverse bias, after a certain voltage (breakdown voltage), the current suddenly increases.
- **Explanation**: In reverse bias, the Zener diode remains non-conductive until the reverse voltage reaches a specific value known as the breakdown voltage. At this point, the diode enters the breakdown region, and a small increase in voltage leads to a large increase in current. This characteristic allows the Zener diode to clamp the output voltage to a stable value.

### Step 3: Connection of Zener Diode in Voltage Regulation
- **Explanation**: The Zener diode is connected in parallel with the load resistor. This configuration ensures that any fluctuations in the input voltage do not affect the output voltage across the load.
- If the input voltage increases, the Zener diode conducts more current, maintaining the output voltage constant.
- Conversely, if the input voltage decreases, the current through the Zener diode decreases, again keeping the output voltage stable.

### Step 4: Conclusion
- Both the assertion and the reason are correct. The Zener diode is indeed used for voltage regulation, and its behavior in reverse bias at the breakdown voltage is what allows it to perform this function effectively.

### Final Answer
- The assertion is true, and the reason is also true. The Zener diode is used for voltage regulation due to its ability to maintain a constant voltage across it when reverse biased beyond the breakdown voltage.

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