The Mullard 5V4G is a full wave rectifier with a maximum rectified output of 175 mA. The minimum series resistance to prevent excessive current flow is 100 Ω.
The twin rectifier sections and the Brimar identification on the Bakelite base cap.
Face view of one anode. Are the holes for decoration or to save metal?
The classic envelope is 44 mm in diameter and, excluding the IO base pins, is 102 mm tall.
References: Data-sheet, Data, 1040 & 1043. Type 5V4G was first introduced in 1937. See also1937 adverts.
