Sensibly equivalent¶ to:
This valve is marked both CV430 and STC 29C1. It is a directly heated diode with an inverted 'W' single strand filament.
John Rehwinkel has supplied data on this exhibit. It is a temperature saturated diode and it was used to measure and regulate voltages. The method was to place the voltage to be measured across the filament and monitoring the anode current. Tektronix used a 2AS15 for the regulation of filament current in some oscilloscopes.
The wide glass tube envelope is 28 mm in diameter, and excluding the IO base pins, is 61 mm tall.
References: Datasheet & John Rehwinkel.
Absolute Maximum Operating Conditions¶
Updated October 06, 2013.