Advanced Qualification · A-007 Feedlines and matching · A-007-002-004
What kind of impedance does a half wavelength transmission line present to the source when the line is shorted at the far end?
- A The same as the characteristic impedance of the transmission line
- B The same as the output impedance of the source
- C A very low impedance
- D A very high impedance
Correct answer: C — A very low impedance. From the official ISED question bank, verified word for word.
Why
When a transmission line exactly half a wavelength long is shorted at the far end, the signal travels down, reflects off the short, and returns to the source with the same phase it started with. The full explanation — and one for every question — is in Pro.
Practise this section
Feedlines and matching at the advanced level: transmission line theory, impedance transformation, stubs and matching networks.