A 15 V Zener diode is used as a regulator. A 20 V source supplies a 250 Ω series resistor and 1 kΩ load resistor in parallel with the Zener. Find Zener current.
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Question

A 15 V Zener diode is used as a regulator. A 20 V source supplies a 250 Ω series resistor and 1 kΩ load resistor in parallel with the Zener. Find Zener current.

G1 Physics · Accepted Answer

Series-resistor drop = 20 − 15 = 5 V, so I_series = 5/250 = 0.020 A = 20 mA. Load current I_L = 15/1000 = 15 mA. KCL at output: I_Z = I_series − I_L = 20 − 15 = 5 mA. Final answer: Option D.