The 3CP1-S1 is an electrostatically deflected cathode-ray tube for use as an airborne radar altimeter. The screen is 75 mm in diameter and has a medium persistence green phosphor.
The main deflector plates can be used to draw a circle and the radial electrode will modulate the circle out from the centre to form a pointer. This was known as a J-scan display.
The once clear transfer on the screen face.
The RCA logo and the 11 pin base.
The pins are equi-spaced and the central spigot has a key as would be found on IO based valves.
The screen with central electrode and screw thread.
Simplified diagram of tube operation.
The end window envelope is 35 mm in diameter and, excluding the base pins, is 35 mm tall.
Reference: Data-sheet. Type 3CP1-S1 was first introduced in 1942. See also1942 adverts.
