The CV4057 is a rugged high voltage half wave rectifier. The CV371 was the predecessor to this rectifier and the CV4042 is the same valve but with flying leads.
In operation this valve can withstand a PIV of 5,000 Volts. The maximum reservoir capacitor value is 1.1 µF and a minimum effective series resistance of 4500 Ohms is required. The peak anode current is up to 180 mA.
This was also made with flying leads for direct wiring in to a circuit.
The KB/E identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the E identifies the maker as Thorn-AEI, Brimsdown.
The high voltage requires ceramic insulators and these can be seen at the top and base of the anode.
The anode broad face with the ceramic beads at each end.
The thin glass tube envelope is 18 mm in diameter, and excluding the B7G base pins, is 51 mm tall.
References: Data-sheet & 1040. Type CV4057 was first introduced in 1958. See also1958 adverts.
