The Brimar 5763 is a small transmitting beam tetrode valve for HF and low VHF use and is equivalent to the Mullard QV03-12. We also have the 5763 with orange lettering.
The circular anode contains a flat sided cathode and grids that are flat across the cathode width and rounded at the ends. The screen grid wires are directly in front of each control grid wire.
The heater is referenced as 6.0 V by RCA, Brimar and Mullard.
John Fielding ZS5JF has sent the following information and the RCA data-sheet.
The 5763 was extensively used as an oscillator, multiplier or power amplifier in HF and VHF equipment. The old Marconi Instruments Q meter variable frequency oscillators used it, also used in the power supply as a series regulator valve. The useful upper frequency limit is about 300 MHz. It was also used as a driver or PA in some early Pye Telecomms VHF mobile radios before being superseded by the twin tetrode QQV03-10 type of valves.
Made in England and BVA (British Valve Association).
Both grids have copper supports.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 58 mm tall.
References: data-sheet & 1040. Type 5763 was first introduced in 1949.