28-10-2017, 05:43 PM
(This post was last modified: 28-10-2017, 05:57 PM by peter scott.)
I came across this little article from Philips Technical Review, November 1936.
http://www.extra.research.philips.com/he...36-321.pdf
Peter
http://www.extra.research.philips.com/he...36-321.pdf
Peter







