question_answer

Name the semiconductor device that can be used to regulate an unregulated dc power supply. With the help of \[I-V\] characteristics of this device, explain its working principle.           

Answer:

                    Zener diode can be used to regulate an unregulated d. c. power supply.                     (i) Zener diode. (ii) Figure (a) shows circuit diagram for forward biasing and Fig. (b) for reverse  biasing of Zener diode. (iii) Figure shows the circuit diagram for using Zener diode as a voltage regulator. When Zener diode is operated in the reverse breakdown region, the voltage across it remains practically constant \[({{V}_{Z}})\] for a large change in reverse current. So any increase/decrease of the input voltage results in, increase/ decrease of the voltage drop across \[{{R}_{s}}\] without any change in voltage across Zener diode. Hence the Zener diode acts as a voltage regulator.