872A

872A has no equivalent designation confirmed by the archive.

The 872A is a mercury vapor rectifier tube of the high-vacuum, high-voltage type, as documented in an Amperex datasheet.

Ratings and Operating Conditions

The 872A has a filament voltage of 5.0 volts and a filament current of 6.75 amperes. A preheating period of 30 seconds is required before plate voltage is applied. For operation at supply frequencies up to 150 cycles, the condensed mercury temperature range is 15°C to 60°C. The approximate tube voltage drop is 10 volts.

For both a peak inverse voltage of 5000 volts and a peak inverse voltage of 10000 volts, the peak plate current rating is 5.0 amperes and the average plate current rating is 1.25 amperes. The average plate current rating is averaged over a period of 15 seconds.

Applications

The Amperex datasheet lists several circuit configurations for the 872A. A single-phase full wave configuration using two tubes supplies 3180 DC output volts to filter at a maximum DC load current of 2.5 amperes, with an AC input voltage of 3535 volts RMS. A single-phase full wave bridge configuration using four tubes supplies 6360 DC output volts to filter at a maximum DC load current of 2.5 amperes, with an AC input voltage of 7070 volts RMS. A three-phase half wave configuration using three tubes supplies 4780 DC output volts to filter at a maximum DC load current of 3.75 amperes, with an AC input voltage of 4080 volts RMS. A three-phase double Y-parallel configuration using six tubes supplies 4780 DC output volts to filter at a maximum DC load current of 7.50 amperes, with an AC input voltage of 4080 volts RMS. A three-phase full wave configuration using six tubes supplies 9570 DC output volts to filter at a maximum DC load current of 3.75 amperes, with an AC input voltage of 4080 volts RMS.

Original manufacturer datasheets for 872A, hosted by Frank Philipse's Electron Tube Data sheets.

Documents held here and used to write this page.

• 872-A - AMPEREX MERCURY VAPOR RECTIFIER

5 further designations appear alongside 872A in the literature but below the evidence threshold used here, so they are not listed as equivalent.