CBSE Class 12-science Answered
(i) Diode used is Zener diode.
(ii) Circuit diagram for Zener diode as a voltage regulator:
(iii) Zener diode as a voltage regulator:
The Zener diode is connected in parallel to external load resistance RL.
Let the unregulated d.c. input voltage Vi is applied to the Zener diode, whose breakdown voltage is VZ. if the applied voltage Vi > VZ , the Zener diode is in breakdown condition. As a result, it easily conducts current through it. Thus depending upon the input voltage, the current in the circuit or through the Zener diode may change but voltage across it remains unaffected by change in load resistance. Hence the output voltage across the Zener diode is a regulated voltage.