Sensibly equivalent¶ to:
This battery double diode triode has a very low filament consumption and is described as an economy valve. It would have been used for detection, AGC detection and first audio amplification in radio receivers. Possible portable military equipment. The MO (Mazda Octal) base dates it as 1938 or after.
The reverse is plain green metallic screening paint.
The classic envelope is 32 mm in diameter and, excluding the MO base pins, is 83 mm tall.
References: Data-sheet, 1040 & 1043. Type HL23DD was first introduced in 1938. See also 1938 adverts.
Absolute Maximum Operating Conditions¶
Updated January 03, 2022.