Development of television includes complex electronics
My personal favorite was Breaking Bad. The storyline was great, the acting was phenomenal, and did you see that ending? Fantastic.
I’m talking about my favorite television show, and, for those of you who aren’t laptop Netflix junkies, the television provides the outlet through which we watch these shows. Beginning in 1897, when J.J. Thompson was able to experimentally deflect cathode rays, the television has had a long and storied history. All-color electronic televisions were first standardized in 1953, but it wasn’t until 1990 that the modern version of digital television became possible.
The first type of television to become industrially popular was the analog television. The analog television contains a cathode ray tube (CRT), which is a vacuum containing an electron gun, a positively charged anode, and a negatively charged cathode. The electrons emitted from the electron gun are negative, so they flow from the cathode to the anode. The electron beam is then concentrated through a device called a focusing anode, after which it hits a phosphor screen on the opposite end of the CRT that glows when struck by high-energy electrons.
In order to scatter the electrons across the screen and produce a full image, a copper wire coil is placed in the CRT. This coil creates a magnetic field when an electron beam is passed through it, and this magnetic field pushes the electrons in varying directions, causing them to scatter across the screen. It is this interaction of electrons and phosphor on the screen that produces a glowing image.
So the CRT creates the image on the screen, but how does a television know what image to produce? An analog television receives two kinds of signals, sounds and pictures, which are typically received either through an antenna, a cable set, or a satellite dish. The picture signal is transmitted over AM signals, and the sound over FM signals, much like AM and FM radio signals. Inside the television, a demodulator receives the FM signal and converts it into a sound signal, which is then converted to sound through the television’s speakers. As for the video signal, a receiver in the CRT takes the AM signal and transmits it as an amplification signal in the electron gun. This signal then modifies the intensity of the electron beam, producing the contrast of images that appear on the screen.
Although this type of television was popular for the majority of the twentieth century, and explains why the television is sometimes called “the tube,” CRT televisions are considered outdated by today’s technological standards. Today’s televisions run on a variety of different technologies, such as the popular liquid-crystal display (LCD). LCD televisions operate in a similar fashion to analog televisions, only instead of using a CRT to beam electrons at a screen it uses cold cathode florescent lamps to beam white light. In order to modify the light’s brightness, LCD shutters are placed in the television. These shutters open and close to transmit a certain intensity of light over an area of the screen. In order to distill out the desired color of the light, each shutter is paired with a color filter to pull out all but the desired color of the light beam.
Television is a relatively modern invention that has advanced from low-resolution, black-and white images to high-resolution, richly colored displays. Televisions rely on a signal input as well as some sort of conversion process to translate the signal into the images that we see on our screens. Even newer forms of technology are developing to create a 3-D television, which takes into account depth perception to simulate a three-dimensional feel on a two-dimensional screen. Now that’s televisionary.