History of Television Technology Presentation

History of

TELEVISIoN

start

Before electical televions, there where mechanical televisions. They started being manufactured in the early 1800's and worked by scanning images and then transmitting those images onto a screen. One of the first mehcanical telvisions used a rotating disk with holes arranged in a spiral pattern. The device was created independently by two inventers called John Logie Baird, who was Scottish, and Charles Francis Jenkins, who was American. Then, the mechanical televisons devleoped by sending scanned images through a wire to a rotating disk but instead of calling it a "television", it was called an "electical telescope". It was then improved by using a cathode ray tube with a scanning system to create a whole new television system Ultimatley, the early efforst of these inventors lead to the first electrical televison to be manufactured in 2 years time.

The First Electrical Television

Between 1926 and 1931, mechanical television inventors continued to tweak and test their creations. However, they were all doomed to be obsolete in comparison to modern electrical televisions: by 1934, all TVs had been converted into the electronic system.

The first electical television was cretaed by a 21 year old inventor called Philo Taylor Farnsworth. Starting in high school, he began to think of a system that could capture moving images, transform those images into code, then move those images along radio waves to different devices. Farnsworth’s system captured moving images using a beam of electrons. The first image ever transmitted by television was a simple line. Later, Farnsworth would famously transmit a dollar sign using his television after a prospective investor asked “When are we going to see some dollars in this thing, Farnsworth?”

How did the Electircal Televisons work?

To control the firing of electrons, CRTs use two “steering coils”. Both steering coils use the power of magnets to push the electron beam to the desired location on the screen. One steering coil pushes the electrons up or down, while the other pushes them left or right.

Electronic televisions rely on a technology called a Cathode Ray Tube (CRT) as well as two or more anodes. The anodes were the positive terminals and the cathode was the negative terminal.The “Cathode” part of the Cathode Ray Tube was a heated filament enclosed in a glass Tube. The Cathode would release a beam of electronics into the empty space of the tube. All of these released electrons had a negative charge and would thus be attracted to positively charged anodes. These anodes were found at the end of the CRT, which was the television screen. As the electrons were released at one end, they were displayed on the television screen at the other end. To make images, the inside of the television screen would be coated with phosphor. The electrons would paint an image on the screen one line at a time.

Timeline of Television Technology

1923

1947

1953

1955

1962

1993

Major Changes of the Television Technology

• Colour TV was invented and introduced in 1954 but only 1% of the population could afford it. It was in 1964-69 when it became common to own a colour TV
• In 1962, Telstar and NASA transimitted the first successful satilite communication. This allowed live broadcasts to be communicated around the atlantic
• Video Tape technology was introduced in 1971 and allowed televison user to record live broadcasts and watch them later or mulitple times.
• In 1979, a Japanese public broadcaster first developed high defintion television with a 5:3 display aspect ratio

Questions!

1.) What were the names of the two inventors who manufactured one of the first mechanical televisions? 2.) Write a brief explanation on the how the mechanical televisions work. 3.) What was the name of the inventor who manufactured the first electrical television and how old was he? 4.) What does "CRT" stand for? 5.) When was coloured TV invented and used? 6.) When was the first successful satilite communication broadcast and who tested it?

Question Answers!

1.) John Logie Beard (Scottish) and Charles Francis Jenkins (American) 2.) It sent scanned images through a wire to a rotating disk. 3.) Philo Taylor Farnsworth and he was 21 years old 4.) Cathode Ray Tube 5.) It was introduced in 1954 but commonly used in 1969 6.) It was first successful in 1962 and was it was tested by NASA and Telstar

1.) What were the names of the two inventors who manufactured one of the first mechanical televisions? 2.) Write a breif explanation of how a mechanical television works. 3.) What was the name of the inventer who manufactured the first electrical televisision and how old was he? 4.) What dpes "CRT" stand for? 5.) When was coloured TV introduced and used? 6.) When was the first successful satilite communication broadcast and who tested it?