This Philips valve is a half wave mercury vapour rectifier. The etched lettering is very difficult to see but says Philips and Made in Holland. No. 1018.
The connections are by three studs on the sides of the base. The filament is rated at 1.8 Volts at 1.8 Amps. It is probably an HT rectifier and the guess is around 220 Volts at 50 mA based on other Philips rectifiers of the period. The filament connections are opposite one another around the base with the anode connection between them.
The internal structure is difficult to see but has suffered a catastrophic failure. The filament was a helix and the anode is a small cylinder. On the left can be seen a long coil of wire that connects between the anode and the pinch and probably is there to limit the current.
A closer view with the coil in the anode lead clearly visible.
The base carries the Philips name.
The thin glass tube envelope is 22 mm in diameter, and including the base is 80 mm tall.
Reference: 3002. Type 1018 was first introduced in 1925. See also1925 adverts.
