Much larger half-wave mercury-vapor rectifier (1.25 A avg, 10 kV PIV); Jumbo 4-pin bayonet base — not pin-compatible
Electrical Specifications
Rectifier
Peak Inverse VoltagePeak Inverse Anode Voltage (max)7,500V
Voltage Drop (typical)Peak Tube Voltage Drop (approx)15V
DC Output Current (max)Average Anode Current (max)125mA
Peak Anode Current (surge)Peak Anode Current (max)500mA
Heater
Heater VoltageFilament Voltage2.5V
Heater CurrentFilament Current2A
Notes
Mercury-vapor tube — must be operated within a condensed-mercury temperature range of 20°C to 60°C. Outside this range, tube life and performance degrade significantly.
Filament must be applied for at least 10 seconds before applying anode voltage, to allow mercury vapor pressure to stabilize.
If ambient temperature is too low, a heat-conserving enclosure or auxiliary heater is required to maintain minimum condensed-mercury temperature.
Shields and RF filter circuits should be provided if the 816 is subjected to extraneous high-frequency fields during operation, as these can cause breakdown effects in mercury vapor.
Peak tube voltage drop is approximately 15 V — substantially lower than vacuum rectifiers of comparable current rating, which is the primary advantage of mercury-vapor types.
Uses Small-Shell Small 4-Pin Base (JETEC No.A4-5) with top cap for anode connection.
In half-wave single-phase service (Fig. 1 in datasheet): max transformer secondary 5300 V RMS, approx DC output 2400 V at 0.125 A (0.3 kW).
The 872A is a much larger mercury-vapor rectifier with 10x the current capacity (1.25 A avg vs 0.125 A), intended for higher-power transmitter supplies.