Sensibly equivalent¶ to:
The DET22 is a physically small disc seal triode valve, with co-axial connections. The DET22 planar valve evolved during WWII as an improved replacement for the CV90. Details emerged in the late 1940's and the attached data sheet is from 1947 supplied courtesy of Risto Kallberg.
The heater and cathode are opposite the main envelope and the emitting surface is a flat topped thimble. The grid has a circular connection to the flat internal metal mesh. The anode is copper and has a flat surface facing the grid and positioned very close to it.
A grounded grid configuration would allow for a two cavity mechanical design.
This valve is rated at 600 MHz but its extended maximum frequency of 4 GHz made it a natural choice for microwave designs.
The planar envelope is 15 mm in diameter and, overall is 60 mm tall.
References: Data-sheet & 1040. Type DET22 was first introduced in 1945. See also 1945 adverts.
Absolute Maximum Operating Conditions¶
Updated January 04, 2022.