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In 1825, British inventor William Sturgeon (1783-1850) introduced the electromagnet, which was a very strong magnet powered by a single cell battery.

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In 1830, an American named Joseph Henry (1797-1878) demonstrated the potential of an electromagnet by sending a current signal throughout one mile, causing a bell to strike.

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In 1835, Samuel Morse (1791-1872) invented a telegraph system. Different signals were sent by an electromagnet and they moved a marker. Translators could decrypt this „morse code“. In 1861, Western Union built their first transcontinental telegraph line.

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improv of the telegraph

telegraph limited to just one message at a time

telephone was the idea for multiple messages at a time

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1870s

Elisha Gray and Alexander Graham Bell

harmonic telegraph = transmit speech electrically

Bell: ‘Mr.Watson, come here - I want to see you’

he came -> first telephone call has been made

Patent on March 7, 1876, quickly began to spread

End of 1880s over 49 thousands telephone US

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they needed to build a working transmitter with a membrane capable of varying electronic currents and a receiver that would reproduce these variations in audible frequencies.

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Late 1800s started

Karl Ferdinand Braun in 1897 invented the cathode ray tube, a forerunner of the TV picture tube

audio waves could be separated from the electromagnetic spectrum to create radio, so too could TV waves be separated to transmit visual images

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In 1904, Italiano inventor Guglielmo Marconi invented the first radio by sending airwaves with the knowledge of Nikola Tesla and Hienrich Herz. He invented it in his attic and asked the Italian government for help, but they weren’t interested so he went to Great Britain and claimed a patent for his invention.

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In 1909, the radio was growing, in the US, rapidly fast and many people had a phonograph.

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In 1914, radios were banned because of World War I and after the solve of conflict in 1919 some small radio stations started a daily program containing sports, music and news.

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In the mid-1920s the number of radio stations was so high, that the US🇺🇸🇺🇸🦅🦅🪖🪖 government had to stop the free use and made a law that rules the airwaves, to hold it under control.

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Mechanical: from Nipkows system, mechanical rotating disks to scan moving images into electrical impulses which were transmitted by cable to a screen, technical limitations and it was quite fuzzy

Eletronic: Baird, developed the model, eletronic beam could scan an image in horizontal lines and almost immediately reproduce the image

1939 it replaced the mechanical system and only wealthy people could buy it

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Between 1930-1950 the radio was used more than ever. During prime time families were listening to their favourite show. Famous programs were the Jack Benny Show and the Bob Hope show. After 1950 the television came up more and more and then more families watched television during prime time.

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It got popular around the 1960s

1954 the tv was made in color by John Logie Baird

Massive growth of popularity

Price was lowered - 60 million TV sets sold

Programs based on radio programs

1950s shows emerged

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The old system had a lot of disadvantages, so mostly in Japan, they invented the digital television

They use a more efficient and flexible form of broadcast technology, it uses signals that translate TV images and sounds into binary code, like a computer. This means they require much less frequency space and also provide a far higher quality picture.

The US invented HDTV, first it was expensive then the prices dropped for everyone