0A4G Gas Regulator Tube – Cold-Cathode Voltage Reference Tube

The 0A4G is a cold-cathode, gas-filled regulator tube from the same family as the 0A3 and 0C3, used to hold a steady reference voltage without a heated filament.

• Tube type: Cold-cathode gas voltage regulator
• Base: Octal 8-pin
• Heater: None (cold-cathode, gas-ionization type)
• Typical use: Voltage reference/regulation in vintage radio and instrument power supplies

Part of the 0-series cold-cathode regulator family — the "0" prefix denotes no heater requirement.