Communications · Vol. VI|Electronic television|1927 (Farnsworth); 1930s broadcasts

Electronic television

1927 (Farnsworth); 1930s broadcasts

Mechanical scanning disks could send a crude picture. Electronic cameras and cathode-ray tubes made a picture people would sit for. Farnsworth transmitted a dollar sign in 1927. By the late 1930s, London and New York had broadcasts. Television is radio with a raster: the world as a sequence of lines, then as a shared evening.

Philo Farnsworth; Vladimir Zworykin; Baird (mechanical) · United States and Britain

Electronic television — Original plate drawn for this atlas. Not a photograph of a museum object or a copyrighted portrait.

How the mechanism is arranged

A beam scans a picture in lines. Persistence of vision stitches the lines into a moving page.

How it works

A camera turns a scene into a stream of electrical samples, line by line.
A transmitter sends that stream as a modulated wave.
A receiver reconstructs brightness on a screen in the same order.

Why it mattered

Made news and drama a domestic, simultaneous event.
Created a mass visual public.
Set expectations later inherited by the smartphone screen.

What it unlocked

For further study

IEEE Milestones. Farnsworth and Zworykin.
Abramson, The History of Television. Survey.

Check

What does a raster do to a picture?