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The Type 82, from 1932, is a full wave mercury vapour rectifier designed for the original American standard AC heater voltage of 2.5 Volts - introduced in the late 1920s.

Like all MV rectifiers it is characterised by a low, and almost constant, voltage drop across the tube when in operation, in this case the drop is just 15 Volts - much lower than a high vacuum rectifier. MV rectifiers need a delay between applying heater power to vapourise the mercury and before applying HT.

The data-sheet describes the 82 as suitable for receivers using a Class B output stage as the HT regulation with the MV rectifier is particularly suited to the large variation in demand current that is a characteristic of the Class B amplifier.

Max Magliaro writes, I have a Grigsby-Grunow Majestic model 320 radio, made in 1932, which uses a type 82 rectifier. The schematic shows it as a type 82.

The etched Type designation is very faint and visible here after some post camera enhancement.

As the Type 82 was designed for domestic equipment the Raytheon label makes sense. In general MV rectifiers are temperamental and reserved for industrial/professional applications.

The construction features ribbon filaments in flattened cylindrical anodes.

The top mica: the filament tension springs connect to the central vertical rods. The ribbon filament can be seen to be oxide coated.

The classic envelope is 44 mm in diameter, and excluding the UX4 base pins is 103 mm tall.

References: Data-sheet, & ¹⁰⁴³. Type 82 was first introduced in 1932. See also 1932 adverts.

Pin Connections

Absolute Maximum Operating Conditions^¶

Thanks to Frank Philipse for supplying the above PDF datasheet.