Uploaded April 2025 | Updated September 2026, 2 weeks ago

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#250 In this video I look at a lesser know type of impedance matching circuit built with a couple short pieces of transmission line - the 12th Wavelength Transformer. Its a very similar concept to the quarter wavelength transformer, however its shorter and it also uses the same impedances as the connecting elements, so you don't really need special transmission line impedance values to use it.

Impedance matching series:
Resistive matching: youtu.be/raw_LAJGvAE
Lossless matching part 1: youtu.be/-_T587mucaI
Lossless matching part 2: youtu.be/cXPJgnmpCrw
Transformer matching part1: youtu.be/cW1Qn0DQwJM
Transformer matching part2: youtu.be/-cG8Q1Mgrtc
Transformer matching part3: youtu.be/-7tXl7y7Ydo
Quarter wavelength matching part1: youtu.be/ie0eBuPohHs
Quarter wavelength matching part2: youtu.be/KLNK935wglA
Stub matching: youtu.be/AbQn6H4j6I0
12th Wavelength Transformer: youtu.be/Bt_hg4ubNoA

References and further reading:
microwaves101.com/encyclopedias/twelfth-wave-transformer
microwavejournal.blogspot.com/2011/09/how-i-developed-sixth-or-twelfth.html
https://www.cv.nrao.edu/~demerson/cs/twelfth.htm
coaxsolutions.com/shop/rg59-mini-white-coax-cable

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