Advanced Qualification · A-001 Advanced theory · A-001-002-005
Why is the resistance of a conductor different for RF currents than for direct currents?
- A Because the insulation conducts current at high frequencies
- B Because of skin effect
- C Because of the Hertzberg effect
- D Because conductors are non-linear devices
Correct answer: B — Because of skin effect. From the official ISED question bank, verified word for word.
Why
At radio frequencies, electric current tends to flow mostly along the outer surface of a conductor rather than through its entire cross-section, a phenomenon known as skin effect. The full explanation — and one for every question — is in Pro.
Practise this section
Advanced theory: time constants, reactance, impedance, resonance, Q, and the mathematics behind tuned circuits.