Advanced Qualification · A-007 Feedlines and matching · A-007-002-003
What kind of impedance does a half wavelength transmission line present to the source when the line is open at the far end?
- AA very high impedance
- BThe same as the characteristic impedance of the transmission line
- CThe same as the output impedance of the source
- DA very low impedance
Correct answer: A — A very high impedance. From the official ISED question bank, verified word for word.
Why
A half wavelength transmission line acts like a mirror for electrical signals, meaning whatever happens at the far end appears exactly the same at the source. The full explanation — and one for every question — is in Pro.
Practise this section
Feedlines and matching is section A-007 of the Advanced exam: Feedlines and matching at the advanced level: transmission line theory, impedance transformation, stubs and matching networks.
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