The 5Z4GT was designed to supply equipment of up to 40 Watts total power, this rectifier was made by several manufacturers. This confirms it as a very popular type. The GT miniature octal type was introduced after the original metal 5Z4 of the mid 1930s, and the standard glass 5Z4G versions had become established. It illustrates the trend to smaller devices.
The twin rectifiers. Around the central cavity are four fins set at right angles to give the maximum area in a small space.
The maximum width of anode is used.
The wide glass tube envelope is 28 mm in diameter and excluding the IO base pins, is 66 mm tall.
References: Data-sheet, 1040 & 1043. Type 5Z4GT was first introduced in 1940. See also1940 adverts.
