Choose the correct statement about Zener diode:
It works as a voltage regulator in reverse bias and behaves like simple pn junction diode in forward bias.
It works as a voltage regulator in both forward and reverse bias.
It works a voltage regulator only in forward bias.
It works as a voltage regulator in forward bias and behaves like simple pn junction diode in reverse bias.
Correct answer:A
Standard Method
Given: The question asks the correct statement about a Zener diode.
Find: Which option correctly describes its behavior in forward and reverse bias.
A Zener diode is designed to operate in the reverse breakdown region. In this region, the voltage across the diode remains relatively constant even when current changes, so it is used as a voltage regulator in reverse bias.
In forward bias, a Zener diode behaves like an ordinary pn junction diode.
Conclusion: The correct option is A. It works as a voltage regulator in reverse bias and behaves like a simple pn junction diode in forward bias.
Concept-Based Explanation
Given: A statement-based question on the operation of a Zener diode.
Find: The correct functional description of the device.
A Zener diode is specially designed so that it can safely work in the reverse breakdown region. At breakdown, the potential difference across it stays nearly constant. Because of this property, it is used for voltage regulation in reverse bias.
When the same diode is connected in forward bias, it does not act as a regulator. It behaves like a normal pn junction diode.
Therefore, statements claiming voltage regulation in forward bias are incorrect.
Conclusion: The correct statement is Option 1, so the answer is A.
Confusing the reverse breakdown operation of a Zener diode with damage in an ordinary diode. A Zener diode is specially designed to operate safely in breakdown; use reverse-bias breakdown as its intended working region.
Assuming that a Zener diode regulates voltage in forward bias as well. In forward bias it behaves like an ordinary pn junction diode, so voltage regulation is not its intended role there.
Memorizing that a Zener diode is a regulator without linking it to bias condition. The key point is that regulation occurs specifically in reverse bias near breakdown voltage.
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