Here is an early experimental sample of the PY33 HT rectifier. This would have been supplied to set manufacturers to evaluate. Clearly it was a success as the PY33 was eventually made by a number of companies.
The PY33 is for television receivers operating with a series heater chain of 300 mA consumption. It operates directly from the mains input and with a series resistance of 25 Ω it will feed a reservoir capacitor of 200 µF. The 300 mA heater was the standard for TV receivers from the 1960s.
The stitched anode with four wings around the central cathode.
The anode was stamped from a single sheet and folded.
The wide glass tube envelope is 32 mm in diameter, and excluding the IO base pins, is 95 mm tall.
References: Data-sheet & 1040. Type PY33 was first introduced in 1961. See also1961 adverts.
