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HMS Collingwood Museum

This valve is a Marconi DE3 triode from 1924.
The filament is rated at 2.8 Volts at 0.06 Amps, this suggests two dry cells in series as the filament supply, but in fact a 4.5 Volt 'bell' battery would be used with a series rheostat. The filament could thus be maintained at the 'correct' voltage. The valve can be used at LF or HF or as a detector according to the label.
The construction is a vertical anode 18 mm long and 5 mm diameter, into which the grid and filament fit coaxially. The filament is a single strand, and the grid is a fine wire helix supported on a side rod through the whole length of the anode.
The wide glass tube envelope is 25 mm in diameter and, excluding the B4 base pins, is 91 mm tall.
 
Pin Connections