Who invented the cathode ray tube?
Q: Who invented the cathode ray tube?
A: Karl Ferdinand Braun invented the cathode ray tube.
Q: What is a cathode ray tube?
A: A cathode ray tube is a type of display that uses an electron gun, a metal electrode (cathode) and an anode to create a vacuum inside a glass tube. The electrons then hit the front of the tube where there is a phosphor screen which lights up when struck by the electrons.
Q: How does it work?
A: The electrons are attracted to the anode and shot out in one direction, creating a cathode ray. To better control the direction of this ray, air is taken out of the glass tube to create a vacuum. The electrons then hit the phosphor screen at the front of the glass tube, causing it to light up. By carefully controlling which bits of phosphor light up, images can be created on the front of this vacuum tube. Changing these images 30 times per second will make them appear as if they are moving.
Q: When was it first used for television?
A: The CRT was first used for modern electronic television by Philo T Farnsworth in 1920s.
Q: When did LCD and plasma screens start being used instead?
A: LCD and plasma screens started being used instead in early 2000s.
Q: What makes CRTs heavy?
A: CRTs are made from thick glass with strong enough vacuums inside them to hold out air, making them quite heavy for large televisions or monitors.
