A Zener of breakdown voltage V Z = 8 V and maximum Zener current, I ZM = 10 mA is subjected to an input voltage V i = 10 V with series resistance R = 100 Ω . In the given circuit R L represents the variable load resistance. The ratio of maximum and minimum value of R L is _____ .

Step-by-step solution

Minimum value of R L for which the diode is shorted is R L R L + 100 × 10 = 8 ⇒ R L = 400   Ω For maximum value of R L , current through diode is 10   mA So, i R = i R L + I ZM ⇒ 2 100 = 8 R L + 10 × 10 - 3 ⇒ 10 × 10 - 3 = 8 R L ⇒ R L = 800   Ω So, R Lmax R Lmin = 2