Virtual Valve Museum

CV101 "crystal valve" S-band mixer diode

This "valve" measures 20x7mm overall (~6mm across the main body)

This valve, actually a semiconductor diode, is designed to operate between 2500 and 6000 MHz.

The CV101 was the first of a range of such devices developed during WWII. See also CV102 and CV103.

Crystal valves were used in the mixers of radar receivers and were susceptible to burn-out caused by the high RF power of the transmitted pulse. It was for this reason that TR Cells were so vital in single-aerial operation, and also the reason for the development of thermionic diode mixers such as the CV58 and CV258.

(Note: Yes I know it is a semiconductor, but as these crystal valves were so vital to radar and many of my other unusual valves are for radar too, surely this deserves to be an 'honorary valve'!)