Larger half-wave mercury-vapor rectifier (1250 mA avg, 10000 V PIV); same Jumbo 4-pin bayonet base family
Electrical Specifications
Rectifier
Peak Inverse VoltagePeak Inverse Voltage (max)5,000V
DC Output Current (max)Average Anode Current (max)250mA
Peak Anode Current (surge)Peak Anode Current (max)1,000mA
Heater
Heater VoltageFilament Voltage2.5V
Heater CurrentFilament Current5A
Notes
Mercury-vapor tube — must be operated within the specified condensed-mercury temperature range. Outside this range, tube life and performance degrade significantly.
Filament must be applied before anode voltage to allow mercury vapor pressure to stabilize.
Uses Jumbo 4-pin bayonet base (1918 pattern) — physically larger than the standard UX4 base. Not interchangeable with UX4-based tubes.
Radiomuseum classifies this as 'Half-Wave Vacuum Rectifier' but other sources indicate mercury-vapor fill. The 2.5 V / 5 A filament and high PIV rating are consistent with mercury-vapor transmitting rectifier practice.
Higher current capacity than the 816 (250 mA avg vs 125 mA) but lower PIV (5000 V vs 7500 V).
Peak anode current rating of 1000 mA allows use in capacitor-input filter circuits with appropriate series resistance.