The CV5745 is the UK Government code for the commercial GZ33 rectifier. This exhibit is unused and came sealed in the original box wrapped in corrugated card and an outer paper wrapper.
The GZ33 shares base pin layout with the GZ32 and the GZ34. All are full wave rectifiers with a rating of 500 Volts for the anodes. The GZ34 is an upgrade to the GZ32 and both are rated at 125 mA rectifier current. The GZ33, however, is a high current version and is rated at 250 mA rectified current, and unlike its lower rated counterparts is not given a maximum reservoir current rating, but 200 µF would seem a maximum value that would be used in practice. The cathode is tied to one side of the heater as heater-cathode insulation would not be sufficient to withstand the full voltage.
Face view of one rectifier section.
The rectifier is indirectly heated as can be seen by the round cathode tubes. The double mica discs would ensure a rigid hold on the glass and reduce the effects of shock and vibration.
The lower mica showing the single hairpin insulated heater. The heaters are wired in parallel.
The classic envelope is 44 mm in diameter and, excluding the IO base pins, is 125 mm tall.
