The PY82 is an efficiency diode for use in domestic television receivers. The valve can also be used for HT rectification. This is an import and PY82 is British Made.
The minimum effective series resistance that must be in circuit to protect the cathode from surges is 30 Ohms. The maximum reservoir capacitor is 60 μF.
The central working anode space is complemented by four side flanges set at right angles to each other to add to the heat radiating surface area.
With the added side flanges the anode fills most of the width of the envelope.
The base and the small cathode tube at the centre of the lower mica. At the top of the image it can be seen that the points on the outside of the mica disc are an interference fit to the glass tube and thus hold the electrodes rigidly in place.
The thin glass tube envelope is 21 mm in diameter, and excluding the B9A base pins is 69 mm tall.
References: Data-sheet, 3002 & 1040. Type PY82 was first introduced in 1951.