Q3Analog Electronics

Question

(B) For the circuit shown in fig. 4, find: (i) output voltage (ii) voltage drop across series resistance (iii) current through zener diode.

Answer 1

Consider a typical Zener regulator with $V_{in} = 15 V$ , $R_{S} = 500 Ω$ , $V_{Z} = 9 V$ , $R_{L} = 1000 Ω$ .

When the Zener diode is in breakdown (which it is, since $V_{in} > V_{Z}$ ), it maintains a constant voltage across the load:

V_{o u t} = V_{Z} = 9 V

V_{R S} = V_{in} - V_{Z} = 15 - 9 = 6 V

Total current from supply:

I_{S} = \frac{V _{R S}}{R _{S}} = \frac{6}{500} = 12 mA

Load current: $I_{L} = \frac{V _{Z}}{R _{L}} = \frac{9}{1000} = 9 mA$

I_{Z} = I_{S} - I_{L} = 12 - 9 = 3 mA

Question