The SD2 is a 2 volt battery triode designed for use as a detector or first stage audio amplifier.
The identification on the envelope carries the makers logo and brief details of operating characteristics. The attached data-sheet is taken from the Triotron 1931 booklet.
The balloon envelope is 48 mm in diameter, and excluding the B4 base pins is 87 mm tall.
References: Data-sheet & 1043. Type SD2 was first introduced in 1929.
Absolute Maximum Operating Conditions¶
PDF scanned from an original document held by the museum
Updated August 11, 2017.