CHAPTER 1 INSPIRATION AND INVENTION Every Every day millions of people pick up their remotes and watch their favorite shows But few understand the science taking place behind the screen A TV is actually part of a system that sends and receives video and audio information First the information is broken down into electronic signals For a TV set to work it must receive sound and picture information 5
Then the signals are sent out Finally a receiver picks up the signals and turns them back into sound and images Inventors of the TV were inspired by radio technology Because sound could be transmitted over the air without wires they wondered if pictures could be transmitted too John Logie Baird built the first TV system in 1926 It used two spinning discs Glass lenses around the first disc picked up light from the object The light hit a photoelectric cell This cell changed the light energy into electric signals The signals were sent by wire to a receiver The receiver used a second 6
The first TV images were not very clear and often flickered spinning disc to create an image of the object It used a process called scanning Starting at one corner the disc created one line of the image at a time Philo T Farnsworth made the first electronic TV in 1927 His TV system used cathode rays instead of spinning discs 7
