Working Principle of CD

Compact Disc (CD):

The Compact Disc is a thin, round plastic platter 12 cms in diameter and approximately one mm thick, with a hole in the centre for a spindle. A poly-carbonate layer of the CD that has the data impressed onto it. It is coated with a mirror-like metal film (Aluminum or Gold). That shiny surface is protected by an over-coating of clear plastic and reflects light in a prism effect.

Features of CD:

As far as CD-ROM is concerned, the main feature of the compact disc is the enormous storage capacity (650 MB) for such a small slim disc and the very high immunity from damage. In contrast to floppy disks and other conventional secondary storage media, the entire CD data is stored in one spiral track. Thus, the stored information can be easily played back at a continuous data rate making this ideal for audio and video output.