Advanced Qualification · A-007 Feedlines and matching · A-007-002-002
What kind of impedance does a quarter wavelength transmission line present to the source if the line is open at the far end?
- A A very high impedance
- B The same as the output impedance of the source
- C The same as the characteristic impedance of the transmission line
- D A very low impedance
Correct answer: D — A very low impedance. From the official ISED question bank, verified word for word.
Why
A quarter-wave line that is open at the far end acts like a short circuit at the source, presenting a very low impedance. 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.