This is an M-OV Type U37 EHT rectifier for oscilloscopes or radar CRTs. It was supplied to enhanced, high reliability, quality standards (hence the Q prefix). The rectifier has a directly-heated oxide-coated filament which is internally connected to the heater. Heater current would normally be supplied via a low-capacity, high frequency transformer powered by the line deflection output or by an auxiliary oscillator.
The voltage rating is quoted as 15 kV PIV (peak inverse volts) and the reservoir capacitor has a maximum value of 0.001 µF. The design maximum DC voltage was 7,500 Volts
The anode bell is supported at one end by the glass/metal seal and the mica disc and side mica sheets. The filament/cathode is secured at the opposite end.
The filament leads and evacuation pip.
The side mica supports.
The thin glass tube envelope is 12 mm in diameter and, excluding the lead-out is 51 mm tall.
References: Data-sheet & 1040. Type QU37A was first introduced in 1952. See also1952 adverts.
