Video camera tube
The video camera tube was a type of cathode ray tube used to capture the television image prior to the introduction of charge-coupled devices (CCDs) in the 1980s. Several different types of tubes were in use from the early 1930s to the 1980s.In these tubes, the cathode ray was scanned across a target which was illuminated by the scene to be broadcast. The resultant current was dependent on the brightness of the image on the target. The size of the striking ray was tiny compared to the size of the target, allowing 483 horizontal scan lines per image in the NTSC format, or 576 lines in PAL.