The SP13 screened amplifier pentode was introduced in 1934. This version has the Ct8 base and the similar SP13C has a B7 base. The use would have been for HF amplification in radio receivers. It is a non variable-mu valve and was displaced in favour of the variable μ pentode when TRF receivers gave way to mass produced superhet receivers.
The classic envelope is 40 mm in diameter, and excluding the Ct8 base pins, is 104 mm tall.
References: Data-sheet, 1040 & 1043. Type SP13 was first introduced in 1934. See also 1934 adverts.
Absolute Maximum Operating Conditions¶
PDF scanned from an original document held by the museum
Updated January 09, 2022.