This Mullard calve carries both the CV2862 UK Government procurement specification Type designation and the commercial AZ31 indicating equivalence.
The AZ31 directly heated full wave rectifier and is fitted with an IO base unlike the earlier AZ1 that had the continental Ct8 base. The AZ31 has identical electrical characteristics to the AZ1.
AZ31 has a 4 Volt filament rated at 1.1 Amp. The maximum anode RMS voltage is 500 Volts. At this anode Voltage the DC current could be up to 60 mA. At 400 Volts on the anode the output could rise to 75 mA and with 300 Volts on the anodes the output current could be 100 mA. The maximum reservoir capacitor had to be no more than 60 µF.
The twin anodes and in the centre the supports for the filament tension springs.
The face view of one anode with the inverted V filament base visible.
The folded anode plates are stitched together.
From the top the filaments can be seen as oxide coated ribbons.
The classic envelope is 44 mm in diameter and, excluding the IO base pins, is 96 mm tall.
References: Data-sheet, 1043 & 3002. Type CV2862 was first introduced in 1949. See also1949 adverts.