EF50

The EF50 was a pentode valve/tube thermionic emission device first manufactured in Holland by the Philips Corporation. The Air Ministry called it VR91 (10E/92), and the Army designation was ARP35 and CV-1091 (KB/DA). The Mullard Corporation in Britain also manufactured it, including the Rodgers Electronic Tubes Limited in Canada, and Sylvania in USA. There were many versions of this valve such as the EFF50, which was a double pentode, and the EFF51, which was a high-frequency amplifier. The EE50 was a special design that made use of secondary thermionic emissions. During The Second World War, the EF50 was used in the British Radar System.

The Air Ministry

ARP35

CV-1091

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