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Sensibly equivalent to:
CV354 TD03-5
See also:
Planar Electrode Valves for VHF
Extras ▼


The DET23 was used in airborne radio. The UK services purchased to a specification from both M-OV and Mullard. The M-OV valves had a black label and the Mullard a white label. Both should have given the same performance, but in practice the M-OV valves had a slight edge. Over time the specification from the RAF altered to favour the M-OV DET23, which then took the greater part of the business.
Technically the difference in the two makes was a slightly thicker wire gauge used in the M-OV for the flying leads. These were made of red platinum at 0.6 mm diameter. The thicker wire increased the problems of achieving a good durable vacuum seal, but avoided the operational dip in performance over a narrow band of frequency. The latter effect being known as 'suck-out'. The DET23 was in production from the post war period up until the mid 1950s.
This physically small disc seal valve has, of course, co-axial connections. The heater and cathode are opposite the main envelope. The grid has a circular connection to the flat internal metal mesh. The anode appears to be copper and has a flat surface facing the grid. For an example of the construction technique see CV90
A grounded grid configuration would allow for a two cavity mechanical design.
The disc seal (glass) envelope is 58 mm tip to tip and the glass is 15 mm in diameter.
References: Data-sheet & 1005.


Absolute Maximum Operating Conditions
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated December03, 2012.
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