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CCDs and CMOS chips, the two kinds of image sensor, do this job in slightly different ways.
Both initially convert incoming light rays into electricity, much like photoelectric cells (used in things like "magic eye" intruder alarms or restroom washbasins that switch on automatically when you put your hands under the faucet).
So it's essentially a digital device where a CCD is an analog one.
CMOS chips work faster and are cheaper to make in high volume than CCDs, so they're now used in most low-cost cellphone cameras and webcams.
It has a built-in microphone and a long USB cable carries both picture and sound to your computer. That sounds like a good idea in theory but, again, it limits you to showing pictures of what is directly in front of the computer.
Other popular cams are made by Logitech, Creative, Hue, and Teck Net.
The image sensor chip is the heart of a webcam—so how does that bit work? Take the outer case off a webcam and you'll find it's little more than a plastic lens mounted directly onto a tiny electronic circuit board underneath.Just like a digital camera, it captures light through a small lens at the front using a tiny grid of microscopic light-detectors built into an image-sensing microchip (either a charge-coupled device (CCD) or, more likely these days, a CMOS image sensor).As we'll see in a moment, the image sensor and its circuitry converts the picture in front of the camera into digital format—a string of zeros and ones that a computer knows how to handle.When you take a digital photo or stare into your webcam, light zooms into the lens.This incoming "picture" hits the image sensor, which breaks it up into individual pixels that are converted into numeric form.