4) For the regulator circuit given below, V, = 21 v, R, = 50 N and Zener diode voltage Vz = 15v with maximum power dissipating Pz(max) = 1.5 Watt. Find a range for the load resistance RL Rs=502 Vs Vz RL Iz(max) Hint: First, find Iz(max) using Pz(max) and Vz; then, Iz(min) 10 +