Concept:Filter capacitors in high-voltage power supplies can retain hazardous charge long after AC power is disconnected. A bleeder resistor provides a discharge path to prevent electric shock.
Formula:$$\tau_{\text{discharge}} = R_{\text{bleeder}} C_{\text{filter}}$$
Solution:- Large filter capacitors store hazardous electrostatic energy (\( E = \frac{1}{2} C V^2 \)).
- When AC mains power is turned off, the bleeder resistor (connected in parallel with the capacitors) discharges the stored energy over a defined time constant.
- It also provides a minimum load current that helps stabilize voltage regulation.
Why other options are incorrect:- Option A: Bleeder resistors slightly reduce ripple by providing a minimum load; they do not increase ripple.
- Option B: The bleeder resistor draws a small quiescent current and does not increase load current.
- Option D: Passive resistors dissipate power as heat; they cannot step up output voltage.
Quality & Fidelity Assurance:
Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.