The Coils.
Ok, so we can see how a beam is produced, but that just hits one point on the screen; we need to create a picture.
There are two steering coils of copper windings able to create magnetic fields. One moves the electron stream vertically, and one moves them horizontally. But varying the strength of these magnetic fields the beam can be focused onto different parts of the screen.
Scanning the screen.
So, now that we can get the beam where we want it on the screen, we need to create the picture. To do this the beam is directed across and down the screen an incredible 50 times every single second.
The screen picture is made up of 625 lines. The beam scans these in an interlaced pattern scanning the odd lines (1,3,5,7,etc) first and then the even lines (2,4,6,8,etc)—that’s a total of 15,625 lines scanned every second.
The Phosphor.
So we can hit the screen anywhere with the electrons, and create the image using a scanning pattern, but how does the picture glow?
Phosphor is any material that glows when hit by radiation. So when the electron beam hits these phosphors they emit the light we see coming from the TV. To produce a colour image there are three phosphors, usually arranged as stripes, which emit red, green and blue light (there are three electron beams to hit each colour phosphor).
Features to look for.
So that outlines in a basic format how the TV produces the pictures we see. But what else can TV now offer us, and how do we get the best out of them?
As mentioned at the start of this piece, TVs don’t just use CRTs anymore. You can buy Plasma screen, LCD screens, and more. But the humble CRT is still going strong because it produces great quality pictures at a price that’s affordable for all, but LCDs are catching up quickly.
Widescreen is obviously still the must have purchase when replacing your TV, but have you though about Real Flat technology? Real Flat screen virtually eliminate the image distortion associated with tradition TV screen. It minimises reflections and increases the viewing angle—great for smaller living rooms.
Or, what about digital integrated sets? As digital TV becomes ever more popular—and the analogue signal being turned off within a few years—integrated sets are becoming more and more popular. This gives you subscription free access to the Freeview channels.
There are also combination TV/DVD/VCR sets to choose from and massive 36” TV also. So the choice is huge and there’s a CRT TV out there to suit you, all based around the amazing technology described above.
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