The PY83 is an efficiency diode for use in television line scan circuits. The peak inverse anode voltage is 5,600 Volts and peak current is 500 mA. The PIV suggests that in sine wave rectification the input voltage would be over 1,000 Volts.
The stitched anode.
Increased surface area for the anode is achieved by opening out the ends and folding them back revealing the polished inner surface of the nickel sheet. This exhibit was Made in England. The heater is separated from the cathode by an insulated helix.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 71 mm tall.
References: Data-sheet, 3002 & 1040. Type PY83 was first introduced in 1951. See also1951 adverts.
