0A3

0A3 has no equivalent designation confirmed by the archive. Completed sales put the typical price at $11.64 per tube.

Construction

The 0A3 is a stabiliser tube, a device consisting of two electrodes placed in an inert gas atmosphere. In the related Mazda OA2 and OB2 stabilisers, the two electrodes are concentric cylinders, one of which, the cathode, is covered with emissive oxides. The choice of electrode materials, the inert gas, and the filling pressure strongly influence the operating conditions of such tubes.

Operating Principle

The discharge in a stabiliser tube is visually observed by a glow whose color depends on the gas mixture used for the filling. The stabiliser tube's static characteristic I=f(V) initially shows the voltage rising without any current flowing through the tube. For a certain anode voltage (the striking voltage), a discharge establishes through the tube, then the voltage remains essentially constant at a value slightly lower than the striking voltage, while the current continues to increase. The voltage difference in a glow discharge tube establishes only in the vicinity of the cathode, while the rest of the anode-cathode space, occupied by equal quantities of positive and negative particles, constitutes the plasma. The potential difference near the cathode, which depends on the nature of the gas and the cathode, defines the stabilisation voltage. Depending on the current intensity through the tube, the discharge covers a larger or smaller portion of the cathode, keeping the current density constant. Once the discharge occupies the entire cathode surface, a further current increase is accompanied by a potential rise, leaving the normal operating zone. The striking of a stabiliser tube is due to three actions: the electrostatic field from the cathode-anode potential, a photoelectric effect, and a radioactive effect.

Ratings

The Mazda OA2 stabiliser has a stabilisation voltage of 150 volts, while the Mazda OB2 stabiliser has a stabilisation voltage of 108 volts. For the OB2 stabiliser, the minimum supply voltage is 133 volts and the current is 138 mA. The Mazda OA2 and OB2 stabilisers have a 5-star version designated 6073 and 6074 respectively.

Per-tube prices from completed sales, 2026-06-10 to 2026-10-04. Matched pairs and quads are divided out. See the price index for how these move over time.

Original manufacturer datasheets for 0A3, hosted by Frank Philipse's Electron Tube Data sheets.

Documents held here and used to write this page.

• CONDITIONS D'EMPLOI DES STABILISATEURS DE TENSION
• Q_Z

1 further designation appears alongside 0A3 in the literature but below the evidence threshold used here, so it is not listed as equivalent.