The Tuneon is a neon tuning indicator. These neon column indicators pre-date the CRT type of 'magic-eye' indicator.
Within the thin glass tube is a wire rod and a pair of circular electrodes. To function as a tuning indicator it produced a column of glowing plasma that changed length by virtue of a changing control potential.
See also 3184 and the 3180 from Cossor.
The working electrode is a simple rod within the tube.
The thin glass tube envelope is 13 mm in diameter and, excluding the base pins, is 103 mm tall.
References: Datasheet & 4010. Type Tuneon was first introduced in 1934.
Absolute Maximum Operating Conditions¶
Updated January 06, 2015. shape:thin.glass.tube construction:pinch type:tuning.indicator age:1930.1940 base: pins:4 pin: