Question

A zener diode provides 6 V voltage to load
resistance (R). If current by battery may vary from
O to 100 mA, what should be the value of R?

Answer 1

E = 9 V = main battery emf supply

Vz = zener diode regulated voltage = 6 V across load

load = RL = 1, 000 Ω

Shunt resistance = Rs = 100 Ω

Let resistance of the zener = r Ω

Since voltage across RL = 6V, current I1 = 6V/1000Ω = 6 mA

Current I = (E - Vz)/Rs

              = (9 - 6) / 100 = 30 mA

So current through the Zener is 30 - 6 = 24 m A = Iz

Equivalent Resistance of zener = 6 V/24 mA = 250 Ω = r

Power dissipation in zener diode = Vz Iz 

      P = 6 V * 24 mA = 0.144 W

Answer 2

Answer:

Explanation:

E = 9 V = main battery emf supply

Vz = zener diode regulated voltage = 6 V across load

load = RL = 1, 000 Ω

Shunt resistance = Rs = 100 Ω

Let resistance of the zener = r Ω

Since voltage across RL = 6V, current I1 = 6V/1000Ω = 6 mA

Current I = (E - Vz)/Rs

              = (9 - 6) / 100 = 30 mA

So current through the Zener is 30 - 6 = 24 m A = Iz

Equivalent Resistance of zener = 6 V/24 mA = 250 Ω = r

Power dissipation in zener diode = Vz Iz 

      P = 6 V * 24 mA = 0.144 W