How does a CD work?
Information is storing in CD as digital format. Pits represent logical 0 and pumps represent logical 1. The CD consist of helical shaped track on the surface. The laser from the drive moves through the track from the centre of the CD to outer edge until the end of the track has been reached. The sensor accept reflected light from the disc and interpret the result.
Your science teacher made a statement about CDs (Compact Discs) that you are not sure you believe. Your teacher said that your music CDs don’t really hold any music on them. “They only have numbers recorded on them,” said your teacher. How is that possible? Your teacher is right in that sound is actually recorded onto the CDs as special numbers – a digital code. This digital code can’t be seen as numbers. The code is pressed onto the CD as bumps on a long spiral track almost five kilometers (3 miles) long. These features look like “pits” on the opposite side of the CD. These pits, bumps, and grooves are an average of 0.5 microns wide (with a minimum of 0.8 microns wide). You need a million microns (a billion nanometers) to equal the length of a meter stick. A small laser beam shines onto the bumps as the CD turns. The light is reflected back to a receiver that records how the laser light bounces back. This lets the CD player turn the reflected light back into the original code. This me
