Advanced Qualification · A-004 Power supplies · A-004-002-010
Excessive rectifier peak current and abnormally high peak inverse voltages can be caused in a power supply by the filter forming a:
- A parallel resonant circuit with the first choke and second capacitor
- B tuned inductance in the filter choke
- C series resonant circuit with the first it choke and first capacitor
- D short circuit across the bleeder
Correct answer: C — series resonant circuit with the first it choke and first capacitor. From the official ISED question bank, verified word for word.
Why
A series resonant circuit forms when the first choke (an inductor that resists current change) and the first capacitor interact at a specific frequency, creating a low-resistance path that allows excessive current to surge through the rectifier. The full explanation — and one for every question — is in Pro.
Practise this section
Power supplies: rectifiers, filtering, regulation, switching supplies and their failure modes.