How Do Televisions Work?

Have you ever wondered, "How do televisions work?" A television screen generates thousands of images every minute, giving off the illusion of smooth motion. Television technology has progressed from early black and white televisions to modern flatscreen panels, but the core concept remains the same.

Televisions were once commonly called "tubes" because each set contained a cathode ray tube. This in turn contains two plates: an anode and a cathode. Electrons passing from the heated cathode through the anode create a beam that shoots toward the back of the television screen. The screen is coated in specks of phosphor, which glow when struck by the electron beam. Each beam produces a point of light, and thousands of these points make up each image on the television screen.

To create color, the specks of phosphor are coated in alternating blue, red and green, and packed together in close proximity. Each electron beam strikes a different combination of these colors with different intensities to create the perception of blended color. On some television sets, these dots are individually visible under close scrutiny.

More modern screens, such as flatscreen televisions and laptop monitors, do not contain cathode ray tubes, and operate differently. Rather than electron beams, the entire screen is lit from behind and displayed through tiny dots called pixels. Each pixel contains three colored filters, much like the colored phosphor of older televisions, and a polarizer to control intensity. The filters blend color for each pixel individually, and display the correct hue.

No matter how old the television, it creates the perception of motion by refreshing the image multiple times per second, according to the television's hertz rate. A 60 hertz television displays 60 images per second. Most media is limited to no more than 30 frames per second, so each frame is usually refreshed more than once, though on televisions with high hertz rates, each frame may be refreshed as many as six times.