Concept:A voltage regulator (such as a reverse-biased Zener diode or linear regulator IC) maintains a constant output voltage by adjusting its conduction to counter input voltage and load current variations.
Formula:$$V_{\text{load}} = V_Z = \text{constant} \quad (\text{in Zener reverse breakdown})$$
Solution:- Rectifiers and filter capacitors produce a DC voltage that can still vary with load current and line fluctuations.
- A Zener diode connected in parallel operates in its reverse breakdown region, holding the load voltage clamp at \( V_Z \).
- This provides a regulated, stable DC output for sensitive electronic circuits.
Why other options are incorrect:- Option A: Transformers operate on AC and cannot regulate a DC output voltage.
- Option C: Fuses provide overcurrent safety protection; they do not regulate voltage.
- Option D: Air-core inductors act as high-frequency chokes rather than DC voltage regulators.
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