Televisions are complex devices and are the result of a century
of invention and development. However, the principles remain the
same and are very simple. A picture is captured by a camera by
breaking the image into a series of dots or pixels across the width
of the picture. Each string of dots makes up one line of the image.
In an HD signal, there are 1920 dots in each line and 1080 lines
from top to bottom. As each dot is captured, the amount of red,
green and blue light is recorded as three numbers. These numbers
are sent as a continuous stream of data. When the whole image has
been sent, the whole process starts over to deliver the next image.
The images are captured 25 or 30 times every second. The television
receives the stream of data and decodes it into a brightness for
each of the three colors in every pixel. There are many other
processes that go on alongside this process but the description
shows the main principle - Identical to the one used by John Logie
Baird in 1925.
A television works by sending and receiving electronic signals.