A Zener diode of breakdown voltage V_Z = 6 V and maximum Zener current I_ ZM = 200 mA is used in a voltage regulator circuit. An unregulated variable DC input voltage V_i is applied to the series combination of a resistor R = 100 and the Zener diode. A fixed load resistor R_L = 150 is connected in parallel with the Zener diode. The Zener diode maintains voltage regulation for the input voltage range V_ V_i V_ . The v

Step-by-step solution

The load current I_L through the fixed load resistor is constant and is given by: I_L = V_Z R_L = 6 150 = 0.04 A = 40 mA For the minimum input voltage V_ , the Zener diode just starts regulating, so the Zener current is approximately zero ( I_Z = 0 ). The total current from the source is I_R = I_L + I_Z = 40 mA + 0 = 40 mA . Applying Kirchhoff's voltage law, the minimum input voltage is: V_ = V_Z + I_R R = 6 + (40 10⁻³ 100) = 6 + 4 = 10 V For the maximum input voltage V_ , the Zener current reaches its maximum allo