Twist Lay Length vs. Inductance at High Frequencies

When I wrote my PhD in 1982,I found an article by a military laboratory on the impedance of twisted magnet wire versus enamel thickness,and pitch of twist.
I shall look after the exact reference,from which the specific inductance can be calculated,as Z = sqrr(L/C) and C is related to the section of the wire,which determines the contact area,and the dielectric permittivity and thickness of the enamel.

Hi Guest,

I look forward to seeing info on that article. I have not yet found that sort of info while looking for it for some years.

BigBirdAustralia

The reference of the paper is:

"Twisted magnet wire transmission line ...";P. Lefferson;

IEEE transactions on parts,hybrids and packaging;Vol PHP7,n°4,december 1971;pages 148 to 154

Dear Guset,

thanks for that reference! I may also have some stuff buried in some older RF textbooks but never ran across Lefferson.

In general the tighter the twist/thinner the coating the lower the transmission-line impedance. It's actually quite easy to obtain 50 Ohms and pass it; I've made ca. 25 Ohm TL in the past and have heard that teens is possible.

Regards

RF_guy

Google "OUTLINE NOTES" "TELEPHONE TRANSMISSION THEORY" W. T. PALMER

Very old and expensive (about $40), but, very good.

Thank you Randall for the hint. I found a copy on BibliOZ for AUD35 and received it today.

Now I will go through its 165 pages.

Just a quick glance shows it is very good in basic theory and will be a good read and reference.

Cheers

BigBird