EFP60 Overview
EFP60 - Secondary Emission Amplifier Almost certainly Philips EFP60 was the first high-frequency amplifier based upon the secondary emission effect. This article, dated August 1939, with the contribution of British Mullard on the Journal of Scientific Instruments allows to date the announcement of the tube just few days before WWII began in Europe. It was probably intended for applications as VHF amplifier in then...
