0B3 / VR90 Voltage Regulator Tube – Cold-Cathode Gas Regulator (90V)

The 0B3 (VR90) is a two-element, cold-cathode gas voltage regulator that holds a steady 90V reference 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

Also cataloged as VR90 — sits between the 0A3 (75V) and 0C3 (105V) in the octal regulator lineup.