The 0D3 is a gas filled discharge valve that exhibits a near constant voltage across the valve for currents within the range 5mA to 40mA. In fact the regulation is 150 plus or minus 5.5 Volts.
Internally pins 3 and 7 are linked. This shorting link is designed to protect the connected equipment from overload, as when the stabiliser is removed the supplied circuit is disconnected.
This Type is also known as VR150, VR150/30 and VT-139. Most are present on this exhibit.
The construction is of a central cold cathode within a cylindrical anode.
The Sylvania name, Made in USA and the US Government procurement code of VT-139.
The )D3 and VR150 are etched into the glass envelope. Construction is of a bright cylinder with a central rod. The geometry is maintained by the locating mica discs.
The top of the central electrode. Near the pinch is the getter holder.
The classic envelope is 38 mm in diameter and, excluding the IO base pins, is 88 mm tall.
Reference: Data-sheet. Type 0D3 was first introduced in 1939. See also1939 adverts.
