How It Works: Old Style TVs
Topics: TV, LCD, Plasma, CRT
The world is moving on from our beloved old clunky televisions to the young, snazzy LCD and plasma screens of the future. But since, in the words of Joni Mitchell, you don’t know what you’ve got til it’s gone, we take one last loving look at how our old tellies worked.
Like the atomic bomb, the television is an example of ingenious science producing a wonderful product that has dramatically changed the world. Just like the a-bomb, its functioning is fascinating and its evils are opposed with gusto.
No one person can claim to be the sole parent of television. It is an example, rather, of expertise from many fields combining to create a collaborative product.
In any electrical circuit through which a current flows, there is a negatively charged end called the anode and a positively charged one called the cathode. In a standard television the cathode ray tube fires electrons from a cathode which are attracted by an anode towards a flat, phosphor-coated screen. Electrified copper windings create a magnetic field that steer the electrons towards a given place on the screen.
By modifying the voltage traveling through the copper windings, the magnetic field can be altered to guide electrons to any position of the screen. The voltage is changed so that the electrons systematically hit every area of the screen, moving the continuous beam in a pattern called ‘raster scan’.
The electron beam travels across the screen similar to the way you would read a book: left to right, then quickly back, slightly down and so on over the entire screen. Then the process repeats itself.
The electron beam moves very quickly, and, in a progressive scan television, a relatively rare type of TV in which the entire screen is updated rather than only half, it manages to hit every portion of the screen 60 times per second. In most TVs, however, the electron beam incorporates a little speed reading known as interlacing and alternates between odd and even rows with each pass over the screen.
When the phosphors on the screen are hit by the electrons, they emit light. In a black and white television, there is only one type of phosphor, but in a colour television there are three different phosphors (emitting red, blue, or green light) and three separate electron beams, one for each colour of phosphor.
Depending upon which phosphors are illuminated, a picture is produced on the screen. As it is updated, the picture changes to give the illusion of motion and the glow of the world’s beloved tube.
Andy worked for four years studying ducks (no stop laughing, he really did). He went into his PhD thinking he was going to save the world (albeit from ducks) and now spends him time lovingly preening Null Hypothesis, the Journal of Unlikely Science!
Previous Articles Highlighter:
Things You Need When Backpacking (1)
You need to maximize the space inside your backpack for things which you need and could really use during your travels. Here are a few tips on what you should bring (yes, some of them are obvious): Clothes.
Golf In Whistler During The Summer (2)
It is a destination known around the world for its spectacular mountains, unsurpassed skiing, limitless outdoor adventures, charming alpine village and now its golf. There was a time when Whistler was really just known for its skiing conditions and terrain, summer used to be the off season.
Tourism Beyond The Winter Olympics (3)
www.Skiatwhistler.com offers real time bookings of premium properties in the world class ski resort of Whistler, British Columbia. Our business is to market property rentals in Whistler to high end vacationers in order to maximize property owners' return on investment (ROI).
Using Your Thermal Binding Machine To Repair Trade Paperback Books (4)
After the book is heated and the glue is soft simply drop the book onto the counter to ensure that the book block is settled securely in the glue and let the book cool.
Mighty Oaks Can Play Important Role In Gardens (5)
In northern climates, the two most important groups of oak are the white and scarlet groups, typically found in native woodlands and which grow well in hardy conditions. In the white oak group, trees have lobed leaves with rounded tips, often widest toward the top.
An Introduction To Indoor Plant Grow Lights (6)
The lack of light is the main inhibiting factor in plant growth. If you reduce the light by 10 percent, you also reduce crop performance by 10 percent. Light transmission should be your major consideration when purchasing a growing structure for a protected crop.
Dividing Irises Is A Natural, Necessary Gardening Job (7)
For Siberian Irises, which cease flowering every three to four years, spring is the best time to divide. Clumps can be separated by hand, once the clump is leveraged with a garden spade.
Do Your Plants Need Hydroponics? (8)
Sufficient light of the correct wavelengths, used by the plant at the growth stage it has reached, is essential for its survival. Plants use lots of light, at least 8 to 12 hours each day, in order to make carbohydrates from CO2 and water.
Variety Of Birds Can Make Gardens Even More Attractive (9)
The good news is that creating a garden atmosphere where birds are welcome is a relatively simply task. Start by thinking about what they need food, cover and water and you'll begin to get the picture.
Hydroponics Uses For The Success Or Failure Of Your Plants (10)
They breathe it in through their tissues and like you, can become sick if it is dirty or contaminated. So, taking these factors one at a time, how can we create the optimum conditions for our plants?
Newer Articles Highlighter:
Go With Used Parts Rather Than New Car Parts (1)
Topics: engines, auto parts, trucks, Jetta, radiator, Chryslers, Use car parts, plastic clips Use car parts are fine to use if you are like me! I like every thing new.
Scrapbooking Ideas To Make A Wonderful Scrapbook (2)
Usually it's quite normal for a scrapbooker to copy other people's styles. With time, the scrapbooker learns and gains the confidence to break free and find her own way and technique.
Replacement For Model Trucks (3)
Double check that the combustion air intake are clear also. You will find it on the right hand side of the furnace. If the air intake is plugged or blocked the burn will not get enough air, which will cause the same problem.
Enjoy The Good Stuff - Download Lost Episodes Today (4)
As the series unfolds, however, it becomes clear that no one is what they seem. This doesn't mean that everyone is secretly working for conflicting government agencies or anything so cliched; the secrets that are hidden are the ones that everyone hides, and some of them are quite dark and deep indeed.
Putting Together An Airplane (5)
Once again I'd recommend that you purchase at least one extra battery. A brushless motor from the major manufacturer will insure a quality motor that will be up to putting out the power.
Watch Out For Predators. Secure Bird Houses (6)
For additional security you can place metal baffles on the pole below the bird house. They will keep away some animals. Another trick you can use to keep the predators away is to mount the bird houses on metal or plastic poles.
Bird Houses Buying Guide (7)
It should also have good ventilation and drainage holes to allow water to drain out. Once you have chosen the best bird house go back to your yard and hang it.
Columbia County Florida: Gateway To The Sunshine State (8)
Topics: Columbia County Florida, Homes For Sale In Columbia County Columbia County Florida is one of the fastest growing areas of the state of Florida with a population that has nearly doubled in the past 25 years.
Citrus County Florida: Home Of The Manatee (9)
With a high quality of life and a relatively low cost of living, tourists often become residents after only a few visits. The city's population remains under 10,000 people, allowing Beverly Hills to combine big-city amenities with small-town charm.
Which RC Car Is Best? (10)
They are charged with electricity that makes the car function. The nitro remote controlled car has a motor. It is powered by fuel just like a normal car.