Type CV717 is a high voltage power full wave rectifier and was designed for providing HT in low power transmitters particularly in aircraft.
The output rating is 180 Watts with a maximum reservoir capacitor of 4 µF. The rectifier needs a series resistance of 250 Ω to limit peak current.
The KB/FB identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the FB identifies the maker as STC, Footscray.
One of the the anodes seen face view. The envelope is etched with the 5R4GY Type designation which is the prototype for this CV specification.
The tops of the anodes showing the ribbon filament and support springs.
The classic envelope is 48 mm diameter at its maximum and excluding the IO base pins the length is 116 mm.
