In the given circuit if the power rating of Zener diode is 10 mW, the value of series resistance Rs to regulate the input unregulated supply is : [figure]
- 10 k
- 10
- 1 k
- 37 k < Rs < 35 k
Answer
(4) 37 k < Rs < 35 k
Solution
[figure]
VRs = 8 - 5 = 3 V, IL = 5 V1 k = 5 mA
IZ, = PVZ = 10 mW5 V = 2 mA, IZ, = 0
Is = IZ + IL 5 mA Is 7 mA
Rs = 3 VIs: 37 k < Rs < 35 k
Answer: (4)