This image is released under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence
Buy this image as a print
License this image for commercial use at Science and Society Picture Library
Science Museum Group
© The Board of Trustees of the Science Museum
Siemens-Schottky valve, type GV15, blue spot on outer grid support, white spot on inner, glass envelope broken, electrodes corroded, (RMW/G52 - McVitie Weston number), by Siemens-Schottky Company Limited, c. 1918.