The Cossor Point One Det & LF is described on its black paper label as designed for rectification (signal detection of AM signals) and low frequency amplification.
The Anode is a variant of the original Tin Hat and is now triangular.
Here the base of the electrodes can be seen. The filament is a single inverted V and both the control grid and anode are shaped to make best use of the shape of the emitting surface.
The top of the anode has an insulator and filament tension spring.
The typical Cossor base cap of the time.
With the microscope the top insulator and helical filament tension spring can clearly be seen. The top of the insulator is shaped to hold the spring in place and likewise so is the base of the insulator as it sits in the anode. A hook from the top centre of the spring descends through the anode to hold the top of the filament.
The balloon envelope is 42 mm in diameter and, excluding the B4 base pins, is 87 mm tall.
References: Data-sheet, 1043 & 1040. Type Point One - Det & LF was first introduced in 1927. See also1927 adverts.
