Television is one of the greatest technological advances of the 20th century
TELEVISION is one of the greatest technological advances of the 20th century.
It was invented by a Scotsman who funded his initial experiments by working as a shoeshine boy and a razor blade salesman.
Several inventors in the USA and Europe were experimenting with television systems in the early years of the last century.
The main feature of his transmitter was a spinning cardboard disc cut from a hat box.
It had holes in it, and inside each was a lens.
The holes were arranged in a spiral, and as the disc turned it scanned the scene in front of it.
Behind the disc was a light-sensitive detector.
German engineer Paul Nipkow (1860–1940) had suggested this set-up long before, in 1884.
The picture produced by Baird’s ‘Televisor’ comprised 30 lines – just enough detail to make out a human face.
In 1925, he succeeded in transmitting the first picture – of a ventriloquist’s dummy named Stookie Bill – from one end of his attic flat in London to the other.
He then paid a local office boy to stand in for Stookie – and the teenager became the first person ever shown on TV.
On January 26th 1926 Baird invited scientists and a reporter to the flat and showed them what he had achieved.
Later that year he formed the Baird Television Development Company Ltd. – and the world’s first television station, 2TV.
In 1927 he sent a live 30-line television signal 730 kilometres (438 miles) from London to Glasgow along telephone cables.
Baird was responsible for several other innovations in television.
In 1928, his company sent the first transatlantic signal, from London to New York.
He also invented an early colour TV system and a disc-based video recording system called Phonovision.
Baird made the first television programmes for the British Broadcasting Corporation (BBC) in 1929.
His broadcast system for the BBC included sound, but never had more than 240 lines – almost the limit of his mechanical system.
Electronic systems would eventually win the day.
In 1936, the BBC began regular television programming using an electronic system and broadcasting pictures with 405 lines.
The receiver in this system was a cathode ray tube: a glass vessel with the air removed and a phosphorescent coating on the inside surface at the front.
A beam of electrons from the back of the tube hits the screen, tracing out the picture line by line, guided by strong electromagnets.
This principle, first suggested in 1897, was still used in most TVs until recently
The most challenging element of the system was the camera.
Russian inventor Vladimir Zworykin (1889–1982) patented the idea for a TV camera tube called the iconoscope in 1923 and it remained the basis for TV cameras until the invention of digital video cameras in the late 1980s.
Television became common in Britain after World War II.
Colour TV was broadcast in the USA in the 1940s but only a tiny proportion of the public had colour sets until the late 1960s.
The first regular colour broadcasts in Britain began in 1967.
It began to reach a wider audience during the 1970s and videocassette recorders (VCRs) became widespread in the early 1980s.
Today, flat-screen LCD (liquid crystal display) and plasma televisions are rapidly replacing cathode ray tube TVs.
Hard disk recorders and DVD (digital versatile disc) recorders have taken over from VCRs.
And more and more people are receiving television via digital signals – either in terrestrial broadcasts, through optical fibre cables or via satellite.
There has also been a huge increase in programmes available on the Internet.