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प्रश्न
Describe briefly with the help of a circuit diagram how a zener diode works to obtain a constant dc voltage from the unregulated dc output of a rectifier ?
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उत्तर
These electrons are responsible for the high current at the breakdown.
Voltage regulator converts an unregulated dc output of rectifier into a constant regulated dc voltage using Zener diode. The unregulated voltage is connected to the Zener diode through a series resistance RS such that the Zener diode is reverse biased. If the input voltage increases, the current through RS and Zener diode increases. Thus the voltage drop across RS increases without any change in the voltage drop across Zener diode. This is because in the breakdown region, Zener voltage remain constant even though the current through Zener diode changes.
Similarly, if the input voltage decreases, the current through RS and Zener diode decreases. The voltage drop across RS decreases without any change in the voltage across the Zener diode.
Thus any change in input voltage results the change in voltage drop across RS without any change in voltage across the Zener Diode.
Thus, Zener diode acts as a voltage regulator.
संबंधित प्रश्न
Describe, with the help of a circuit diagram, the working of Zener diode as a voltage regulator.
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Consider the following statements (A) and (B) and identify the correct answer.
(A) A Zener diode is connected in reverse bias when used as a voltage regulator.
(B) The potential barrier of the p-n junction lies between 0.1 V to 0.3 V.
What happens during regulation action of a Zener diode?
- The current in and voltage across the Zenor remains fixed.
- The current through the series Resistance (Rs) changes.
- The Zener resistance is constant.
- The resistance offered by the Zener changes.
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