This CV5809 is a special quality high slope pentode designed for use in industrial equipment where stability of characteristics and long life are required. It is a wideband RF device, but no frequency range is given. From the information available it appears that 40 - 100 MHz is a probable upper value. Oscilloscope amplifiers and other measuring instruments are likely candidates for this valve. We believe that this valve dates from the 1960s.
The base pins are gold plated for long life connections without corrosion.
The KB/ identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority the maker identification code is missing.
The anode covers the inner structure. The top mica is doubled and this was shown to allow a long life when used in areas of shock and vibration. A single mica rapidly lost definition of the holes and made the electrodes move with a consequent loss of characteristics.
The anode is folded to give both extra area and to present a small section close to the grids.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 46 mm tall.
References: Data-sheet & 1040. Type CV5809 was first introduced in 1958. See also1958 adverts.
