A voltage regulating circuit consisting of Zener diode, having breakdown voltage of 10 V and maximum power dissipation of 0.4 W, is operated at 15 V. The approximate value of protective resistance in this circuit is .
Answer
125
Solution
Maximum current through the Zener diode: Imax = PmaxVZ = 0.410 = 0.04 A
Voltage across the protective (series) resistance: 15 - 10 = 5 V
R = 50.04 = 125
Answer: 125