How a Digital Camera Works

How a Digital Camera Works

by: Jakob Jelling

The digital camera is not something of a magic box that came out of the blue and made wonders! The digital camera is very much like the conventional analog camera, but the technology has been altered. It also contains most of the associated components that the conventional camera contains, like lens and a shutter for letting in light, however instead of reaching a photosensitive film, the light is made to fall upon array of image sensors or photosensitive cells. Much of the differences are like this, yet most of it still remains in oblivion for the ordinary people. And it order that the digital camera gets its true respect, it is necessary to explore these areas of truth and reveal them in light.

Looking a bit more in details about the working of the fantastic device, the digital camera. As a continuation of the above lines, it can be further investigated that the sensor array is basically a microchip about 10 mm across. Every image sensor is a chargedcouple device (CCD) converting light into electric charges, and is essentially a silicon chip used to measure light. These charges are stored as analog data that are then converted to digital via a device called an analog to digital converter (ADC). Over the chip are present a collection of very small lightsensitive diodes, named photosites, or pixels that convert light (or more scientifically, photons) into electrical charges called electrons. The pixels are very much light sensitive, therefore with brighter light striking them, produces greater build up of electrical charges. Each 1000 array receptor creates 1 pixel, and every pixel corresponds to some information stored. The light enters the digital camera via the lens, which is the same mechanism as the conventional analog camera. And this light hits the CCD when the photographer presses the shutter button. The shutter opens and thereby illuminates every pixel, however with various intensities.

Taking a look apart, it can be observed that quite a few digital cameras use CMOS (meaning complementary metal oxide semiconductor, a technology of manufacturing these microchips) technology based microchips as image sensors. The basic advantage is that the CMOS sensors are appreciably cheaper and simpler to fabricate than CCDs. Another great advantage from CMOS sensors is that these take very less power compared to other technology, which adds up to the fact as to their extensive use, and can thus even support the implementation of additional circuitry on the same chip like ADC, some control units etc. Thus it can be stated that CMOS technology based cameras are small, light, cheap and also energy efficient, yet at the cost of some amount of image quality.

However the common trend remains that all cameras of the mega pixel range and higher up use CCD chips instead of CMOS. This is because of the fact of picture quality only, leaving aside the price differences.

This is basically the fact about how digital cameras work! Having known this much difference would not come in the photographing expertise of the users, but it always feels a kind of satisfaction on understanding the inner depths of a device that is so close to the eyes!

By Jakob Jelling

http://www.snapjunky.com

About The Author

Jakob Jelling is the founder of http://www.snapjunky.com. Visit his digital camera guide and learn how to take better pictures with your digicam.

This article was posted on October 20, 2004

by Jakob Jelling

Your Computer Can’t Keep Time

Your Computer Can’t Keep Time

by: Stephen Bucaro

A computer needs a certain amount of information to operate; for example, the date and time, the amount of memory installed, the number of drives and their configuration, and so on. In the early days of computers, either the user typed in this information each time the computer started, or it was set using DIP switches and jumpers. Today, computers store this information in a CMOS chip that uses a small battery to retain the information when the computer is shut off.

CMOS (complementary metal oxide semiconductor) is type of chip that consumes very little power; therefore, while the computer is turned off, the battery discharges very slowly. But the battery will totally discharge if you leave your computer turned off for a year or so. Even if you turn your computer on every day, the battery is designed to last only a couple of years. Occasionally a battery will fail prematurely.

Todayกs plugandplay computers can detect most of the necessary settings, but if your CMOS battery is dead, your computer will not be able to retain the date and time. The computer will also lose any custom settings, for example, the boot sequence. If you set a password in CMOS, you may be locked out of the computer. If the CMOS battery does fail, you might receive the message กSystem Configuration Lostก when you start the computer. It would be wise to record all the CMOS settings as a precaution.

To record the CMOS settings, watch for an onscreen prompt when you first start your computer. The prompt tells you to press a key, usually the Del or F2, to enter CMOS. To enter the CMOS configuration utility, you have to press the indicated key while the message is on the screen. After the CMOS configuration screen appears, follow the instructions provided to page through all the screens and record all the settings.

If your computer loses its time setting overnight, the CMOS battery may not be holding a charge. The CMOS battery is located inside the case on the motherboard. Changing the battery is usually a job for a computer technician. In fact, a layman might not even be able to find the battery.

If you want to locate the CMOS battery in your computer, be aware that a static discharge from your hands can damage components inside the case. After taking proper precautions, open the case and look on the motherboard for a battery. If you have a diagram of your motherboard, locate the battery on the diagram first.

Different motherboards use different types of batteries. The battery may be shaped like a barrel or a coin. Some motherboards use a component that resembles a chip which contains the CMOS and the battery (made by DALLAS or Benchmarq). Batteries come in different voltages, so make sure you get an exact replacement.

Sometimes the battery is mounted in a holder. Sometimes it is soldered to the motherboard. Desoldering and resoldering a battery is usually a job for a computer technician. An inexperienced solderer can cause a lot of damage. If you want to try to do it yourself, first practice on an obsolete circuit board. You may change your mind.

If the CMOS battery has failed because itกs too old, this might be an opportunity to upgrade your motherboard. When upgrading a motherboard, the most important considerations are to make sure the new motherboard is the correct form factor for your case, and that the new motherboard has the correct bus connector slots for your expansion boards.

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About The Author

Stephen Bucaro

To learn how to maintain your computer and use it more effectively to design a Web site and make money on the Web visit bucarotechelp.com To subscribe to Bucaro TecHelp Newsletter visit http://bucarotechelp.com/search/000800.asp

This article was posted on September 09, 2004

by Stephen Bucaro