Colour TVs

The first colour TVs appeared in the 1950s and became more and more popular in the 1960s.
A colour TV works like a digital camera’s pixel system. It uses the primary colours (red,
green and blue) to create other colours. You can use a magnifier to look closely at a colour TV screen.
When you look closely, you can see hundreds of thousands of pixels. Each pixel has three lights,
each in one primary colour. When all these lights turn on, you see white, and when they all turn off, you see black.
The lights in a pixel work together to create other colours.
For example, a little bit of red and a little bit of green can give you a dim yellow.
If both red and green are fully turned on, you can see a bright yellow.
The pixels light up from left to right and from top to bottom to create one picture frame.
The number of times a TV screen shows picture frames in a second is called the refresh rate.
Older TVs showed 60 frames a second, but today’s TVs show 120 to 240 frames per second.
Pixels on old colour TVs were big. Today you need a strong magnifier to see the pixels on an LCD television.