The Cossor P2 is a bright emitter valve and first went into production in 1922. Cossor launched the valve as for HF use. This is an early production model as the base cap is metal, later versions had a plastic cap.
The fan shaped anode was much hyped in Cossor adverts. The grid is a series of loops echoing the fan shape. The single strand filament is formed into an arc.
The red paint distinguishes the P2 from the P1, otherwise they look the same.
The base insulating insert was made by CVC Ltd. The connecting pins are of simple split-pin construction.
The control grid wound as a series of loops and held in place by the tabs on the frame.
The original box.
With the microscope the grid loops and the filament can be seen. Clarity is spoilt by looking obliquely through the glass envelope.
A closer look at one side of the grid, clearly showing the method of retaining the loops.
Part of the filament.
The wide glass tube envelope is 29 mm in diameter, and excluding the B4 base pins, is 79 mm tall.
References: 1003. Type P2 was first introduced in 1922. See also1922 adverts.
