Summary

The PM24 was the Mullard equivalent of the Philips B443, the first commercially available pentodes, released in 1928.

The pentode was developed by Bernard Tellegen at the Philips Research Laboratories in The Netherlands. Mullard was a wholly owned subsidiary of Philips by 1928 and manufactured Philips valves for the British market using their own type numbers prefixed by PM standing for 'Philips-Mullard'. Philips and Mullard had separate marketing operations in Australia from the 1920s until the 1960s. Philips also had manufacturing facilities and valves made by them in Australia were marketed under both Philips and Mullard names.

They also made a number of types which had no Philips equivalent but still used the PM prefix.

4 volt directly heated cathode.

Manufacturer: Mullard, England.

Physical Description

4 pin European style base with side terminal; glass bulb removed. On display block with ST 21581

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