The PY800 was one of the last rectifiers of its type to be developed and is based on the PY81 from 1952. It was specifically built as an efficiency diode for television line scan in sets using 110° deflection angle tubes.
Considerable energy is fed to the line deflection coils and this has to dissipate during flyback. The efficiency diode channels this energy back to the supply rail smoothing capacitors for use on the next line scan.
The rectifier is specified as having a peak inverse voltage rating of 5,750 Volts, and a peak current rating of 450 mA. For sine wave use an input voltage of 1,500 Volts at 175 mA could be rectified. No voltage drop is quoted so the dissipation can not be given.
The Pinnacle logo and the word Foreign denoting an import and implying an inferior product. The ends of the anode are opened out to include the greater area within the glass cylinder.
The two parts of the anode are stitched together. The cathode can be seen connected to the top cap whereas the anode connects to the base pins.
The thin glass tube envelope is 21 mm in diameter and, excluding the B9A base pins, is 71 mm tall.
References: Datasheet & 1040. Type PY800 was first introduced in 1961.