UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Interesting Armstrong AM detector circuit.

Argus25 · 29th Oct 2017, 12:22 am

Ukol,

That formula should have read 0.275/RC. That is if one goes by remarks in Terman about the AC impedance and DC resistance of the detector. I calculated it two other ways and got between 0.5/RC and 0.3/RC, so it's in this vicinity.

Right now I'm on an iPad having some difficulty copying and pasting addresses. If you go to one of my websites which is just a repository for articles in PDFs format,

www.worldphaco.com

and hunt around on the right side of the page for the article on Radio Grid Leak Detectors in the 1920's , it is explained in there how the formula was calculated. Then that link could replace the general website link above in this post.

I investigated it because I was curious about why grid leak resistors in the 1920's had colourful marketing claims for different tones etc.

29th Oct 2017, 12:22 am	#16
Argus25 No Longer a Member Join Date: Oct 2016 Location: Maroochydore, Queensland, Australia. Posts: 2,679	Re: Interesting Armstrong AM detector circuit. Ukol, That formula should have read 0.275/RC. That is if one goes by remarks in Terman about the AC impedance and DC resistance of the detector. I calculated it two other ways and got between 0.5/RC and 0.3/RC, so it's in this vicinity. Right now I'm on an iPad having some difficulty copying and pasting addresses. If you go to one of my websites which is just a repository for articles in PDFs format, www.worldphaco.com and hunt around on the right side of the page for the article on Radio Grid Leak Detectors in the 1920's , it is explained in there how the formula was calculated. Then that link could replace the general website link above in this post. I investigated it because I was curious about why grid leak resistors in the 1920's had colourful marketing claims for different tones etc.