0Y4 Gas Rectifier Tube – Cold-Cathode Half-Wave Rectifier

The 0Y4 is a half-wave, cold-cathode gas rectifier with a starter anode, used to rectify AC into DC without a heated filament.

• Tube type: Cold-cathode gas rectifier
• Base: Octal 8-pin (5 pins wired)
• Heater: None (cold-cathode, gas-ionization type)
• Typical use: Rectifier stage in vintage radio and instrument power supplies

Rated for a moderate 40-75mA current range — a lighter-duty cousin of the 0Z4 full-wave rectifier.