The information given here is based on my own experience with a variety of gas tubes.

Regulators
(Spannungsstabilisierungsröhre in German)

991 (same as NE-16): A simple neon tube spec'ed as a regulator. Current: 0.4 to 2.0 mA. Voltage: 48 to 67 V(!). Not much of a regulator.

874: RCA's first gas regulator, from 1925. Current: 10 to 50 mA. Voltage: 90V. Best left to the antique radio collectors.

0A3 per VR-75, 0B3 per VR-90, 0C3 per VR-105, 0D3 per VR-150: The workhorse octal regulators from the late 1930s. Current: 5 to 40 mA. Voltage: see VR number. The 105 volt 0C3 has, on the average, much better regulation than the other types. The 0B3 is rare.

0A2, 0B2, 0C2: Miniature versions of the 0D3, 0C3, and 0A3, respectively. Developed during World War II. Current: 5 to 30 mA. Voltage: 0A2 - 150V, 0B2 - 150V, 0C2 - 75V. Like the 0C3, the 105 volt 0B2 has the best regulation.

6073 per 0A2WA, 6074 per 0B2WA: Military ruggedized versions of the 0A2 and 0B2 from the early 1950s. Tighter tolerances and more rugged, but otherwise identical to the regular types.

5787WA: A subminiature regulator from Raytheon. Current: 5 to 25 mA. Voltage: 100 V.

90C1: European 90 volt miniature regulator. Current: 1 to 40 mA.

100E1: A giant European 100 volt regulator with a European 4-pin "A" base. Current: 50 to 200 ma (!).

150C1, 150C1K: European versions of the 0D3. The 150C1 has the side contact "P" base and the 150C1K has an octal base.

References
(Präzisionsspannungsstabilisierungsröhre
in German)

5651: RCA's design from 1948. Current: 1.5 to 3.5 mA. Voltage: 5651: 87 V, 5651A: 85.5 V. The most popular American reference.

5783WA: A subminiature reference from Raytheon. Current: 1.5 to 3.5 mA. Voltage: 85 V.

0G3 per 85A2: A European version of the 5651 with tighter specs. Current: 1 to 10 mA. Voltage: 85 V.

85A1: A European 85 volt loctal reference. Current: 1 to 8 mA.

83A1: A late (1960) Philips miniature reference with very tight specs. Current: 3.5 to 6.0 mA (4.5 mA preferred). Voltage: 83 V.

Corona Regulators
   One of the more interesting gas regulators is the very high-voltage corona regulator. In America, these were made by Victoreen and Raytheon, and came in envelopes ranging from subminiature to 9-pin miniature. They operate on the principle of the corona discharge that happens before the normal plasma discharge develops. In fact, they can be destroyed if allowed to go into a full discharge. The rated voltages go from about 500 V to 2000 V and the operating currents are in the tens of microamperes, depending on the size of the tube. These tubes were often used as regulators for oscilloscopes and Geiger counters.


                                 // JA