Tag Archives: LED


OK, I admit it I went on a little about this 🙂

Here is a good post on the working of a scanner and in researching it I found that the video (below) in question was correct for colour CCDs.

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We will look at CCDs in more detail in next weeks lesson.

Here is a take apart that shows a LED scanner in more detail 🙂

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Printers and screens

Today we learned all about printers and all the different types that you get, including their cartridges and about different types of screens.

Mr Stratton began by recapping what we had talked about in the previous lessons, cameras, analogue to digital converters, videos etc.

He began the lesson by taking the printer to pieces to show us the cartridge and explained that not all of them contain bombs. Ink-jet printers are based on a mixture of three different types of technology : continuous flow ink-jet, liquid ink jet and phase-change ink-jet. Mr Stratton then went on to explain about how liquid ink-jet works. Liquid ink-jet works by squirting tiny drops of ink onto the paper, the ink is firstly heated up by the electric current through a coil, this creates a bubble which then forces the ink from the printer to the paper.
We then went on to talk about how laser printers work. Mr Stratton went on to explain that the lasers “write” a page image onto a special drum as an electrostatic charge, the charged drum draws the toner particles which then transfers onto the page to make an image.

In today’s lesson we also learned about different types of screens/monitors. We learned that multi-screen monitors are used for desktop computers and are based on technology which is similar to that of a TV screen, these both use a CRT-Cathode Ray Tube. CRT improves the quality of the images on screen. A Cathode Ray Tube is a miniature version of the lights that are in a classroom and are meant to last roughly 10,000 hours but because of the size and different parts required to make it work it turns out to be reasonably complicated and expensive to make. TFT-Thin-Film Transistors are much more robust as they are a lot cheaper to produce and do not take as much time to make. This means that overall it would be practical to use a TFT monitor rather than a CRT just because they are a lot more reasonable in price, however, the CRT is actually better because the screen is brighter and far more realistic.

We then began to have a natter about how TFT screens brake if they are twisted unlike the latest LED screens that are able to be moulded for flexibility. So if you want a laptop that rolls up like a newspaper in your pocket you might want to wait till they are released.

To end the lesson Mr Stratton then began to talk about- “the project“. He spoke about how the old exams used to be and how you could pick your own subject and work away at it, which he loved, and how it has now changed so that we all have to do the same, which he doesn’t really like that much. He also mentioned what he aims to do tomorrow-give out two different projects to the separate groups, tell us to decide what is good and which is bad, give them a mark and then give us the marking scheme= tomorrows lesson.

That’s all folks. 🙂