Video camera tube facts for kids
A video camera tube was a special electronic device. It was like an "eye" for early television cameras. These tubes were used to capture images for TV shows and news from the 1930s until the 1980s. They helped turn what a camera saw into an electronic signal that could be shown on a TV screen.
Contents
How Video Camera Tubes Worked
Video camera tubes used clever technology to capture light and turn it into a picture. They had a few main parts that worked together to make this happen.
Seeing the Light
First, a lens focused the image onto a special material inside the tube. This material was called a photoelectric material. It's "photo" because it reacts to light, and "electric" because it produces tiny particles called electrons when light hits it. Imagine it like a tiny screen that gets charged up by light. The brighter the light, the more electrons it would release.
The Electron Gun
At the back of the tube, there was something called an electron gun. This gun was similar to the one found in old cathode ray tube (CRT) televisions. It fired a steady stream of electrons towards the photoelectric material at the front. These electrons would "scan" across the material very quickly, like a paintbrush moving across a canvas.
Making the Picture Signal
When the electrons from the gun hit the photoelectric material, some of them would bounce back. The number of electrons that bounced back depended on how much light had hit that spot on the material. If a spot was very bright, the material would have released more of its own electrons, causing more of the gun's electrons to bounce away.
By measuring how many electrons bounced back from each tiny spot, the video camera tube could figure out how bright each part of the image was. This information was then turned into an electronic signal. This signal was perfect for sending to a cathode ray tube television, which would then use it to display the picture on your screen.
Related Pages
Images for kids
-
A display of a variety of early experimental video camera tubes from 1954, with Vladimir K. Zworykin who invented the iconoscope
-
Farnsworth image dissector tube from 1931
-
Zworykin holding an iconoscope tube
-
Dark halo around bright rocket flame in television of John Glenn's liftoff of Mercury-Atlas 6 in 1962
-
Schematic of vidicon tube.
-
The electron gun from an RCA Vidicon camera tube.
-
Schematic of a Plumbicon tube. (This image is schematic, not to scale; a Plumbicon has the same shape as a vidicon.)
