Category: Volume 21

On the Cover On The Cover: A British playing card promoting the Mazda brand. In this issue

On the Cover On The Cover: Early ’20s Philips poster. In this issue

On the Cover On The Cover: Promotion of the Belgian tube marketing firm. In this issue

On the Cover On The Cover: Promotion of the Dutch tubemaker Thermion Radio-Lampenfabriek. In this issue

On the Cover The “Voltage Amplifier Tube – Huth” with a clip-in ballast resistor matched to its filament drain, from the Dr. Erich F. Huth Gesselschaft just after WW1. In this issue

On the Cover The Telefunken 201, a field-effect device using a sprayed-zinc coating as the control electrodet. In this issue