The PY80 is an early efficiency diode for television line scan systems and was part of the world series valves introduced by Mullard in 1950.
A plan view of the anode would show a right angled cross form. Here the two parts can be seen to be stitched together. The other branches of the cross are folded flanges.
The central cathode is a cylinder.
The maximum peak inverse voltage on the anode has to be under 4 kV. The peak heater to cathode voltage has to be under 650 Volts.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 69 mm tall.
References: Data-sheet & 1040. Type PY80 was first introduced in 1950. See also1950 adverts.
