Television is unquestionably one of the most powerful powers of our era. You can watch news, sports, entertainment, information, and ads on a television set, also known as a TV. The average American spends two to five hours per day hooked to the television!
Have you ever pondered how television is made possible by technology? How come you get dozens or hundreds of channels of full-motion video delivered to your door, often for free? To produce a picture, how does your television decipher the signals? What impact will the new digital television signals have? Read on if you’ve ever been curious about your television (or, for that matter, your computer monitor)! We’ll answer all of these questions and more in this article. To get started, go to the next page.
Pixels on TV and Your Mind
Let’s start at the beginning with a brief description of your brain. There are two great features about your brain that allow you to watch television. You can learn a lot about why televisions are designed the way they are by studying these two truths.
The fundamental concept is that if you break down a still image into small coloured dots, your brain will reassemble the dots into a meaningful image. As any researcher who has attempted to design a computer to read photographs can attest, this is no easy task. Only by blowing up the dots to the point where our minds can no longer combine them can we realise that this is actually happening:
The dots are too huge for your brain to grasp, so most people can’t determine what this is a picture of when they’re sitting right up close to their computer screens. However, if you stand 10 to 15 feet away from your monitor, your brain will be able to piece together the dots in the image and recognise the baby’s face. The dots grow small enough for your brain to merge into a recognised image when you stand back.
To split up visuals into thousands of separate pieces, televisions and computer screens (as well as newspaper and magazine shots) rely on the human brain’s fusion-of-small-colored-dots capabilities. Pixels are the dots on a TV or computer screen. The screen resolution on your computer could be 800×600 pixels or 1024×768 pixels.
The Cathode Ray Tube is a type of cathode ray tube.
A few modern televisions employ a mechanism called a cathode ray tube, or CRT, to display their images. Other common technologies include LCDs and plasma screens. Thousands of common 60-watt light bulbs can even be used to construct a television screen! Something similar like this may have been observed during an outdoor event such as a football game. But let’s start with the CRT.
In electronics, the phrases anode and cathode are interchangeable terminology for positive and negative terminals. The positive terminal of a battery, for example, could be referred to as the anode, and the negative end as the cathode.
The “cathode” of a cathode ray tube is a heated filament (not unlike the filament in a normal light bulb). A vacuum is created inside a glass “tube” to contain the heated filament. The “ray” is a stream of electrons that naturally flow into the vacuum from a heated cathode.
Electrons have a negative charge. Because the anode is positive, it attracts the electrons that are ejected from the cathode. The stream of electrons in a TV’s cathode ray tube is focussed into a tight beam by a focusing anode and then accelerated by an accelerating anode. This tightly focused, high-speed beam of electrons passes through the tube’s vacuum and lands on the flat screen at the other end. This screen is made of phosphor, which illuminates when the beam hits it.