Q.
A zener diode of voltage VZ(=6V) is used to maintain a constant voltage across a load resistance RL(=1000Ω ) by using a series resistance Rs(=100Ω). If the e.m.f. of source is E(=9V), what is the power being dissipated in Zener diode?
Here, E=9V;Vz=6;RL=1000W and Rs=100W
Potential drop across series resistor V=E−VZ=9−6=3V
Current through series resistance RS is I=RV=1003=0.03A
Current through load resistance RL is IL=RLVZ=10006=0.006A
Current through Zener diode is IZ=I−IL=0.03−0.006=0.024amp.
Power dissipated in Zener diode is PZ=VZIZ=6×0.024=0.144 Watt