Zener diode as a simple regulator In a low-power supply, a properly biased zener diode (with a series current-limiting resistor) can be used to maintain a nearly constant output voltage across a load over a reasonable current range. Is this use of a zener diode valid for voltage regulation?

Introduction / Context:
Zener diodes are classic references for simple shunt regulators. When reverse biased into the breakdown region (within rated current and power), the zener maintains a near-constant voltage that can stabilize a supply for small loads or provide a reference for more elaborate regulators.

Given Data / Assumptions:

• Zener diode with specified breakdown voltage V_Z.
• Series resistor to limit current from the unregulated source.
• Load drawing current within the zener’s regulation range and power rating limits.

Concept / Approach:
With a source V_S, series resistor R_S, and zener in shunt, the current through R_S splits between the zener and the load. As V_S or load current varies moderately, the zener current adjusts so that the voltage at the node remains approximately V_Z. The design uses Ohm’s law and power limits to ensure I_Z stays between I_Z(min) for regulation and I_Z(max) for safe dissipation.

Step-by-Step Solution:

Verification / Alternative check:
Measure V_out against changes in load; within the designed range, the output stays close to V_Z with small deviations due to dynamic resistance and temperature coefficients.

Why Other Options Are Wrong:

Common Pitfalls:
Omitting the series resistor; ignoring zener power dissipation at light load; expecting tight regulation under large line/load swings or high power (use series pass regulators in such cases).

Final Answer:
Correct