A standard Compact Disc (CD) measures 4.7 inches (120 millimeters) across and is 1.2 mm thick, designed for storing audio and data.
Standard CD Specifications
Compact discs have remained a consistent standard in terms of physical dimensions and storage capabilities since their introduction. Here's a detailed look at the key specifications of a typical CD disc:
| Specification | Measurement |
|---|---|
| Diameter | 4.7 inches (120 millimeters) |
| Thickness | 1.2 millimeters |
| Weight | 15 grams to 20 grams |
| Audio Capacity | 80 minutes |
| Data Capacity | 650 megabytes (MB) to 700 megabytes (MB) |
How a CD Works
Beyond its physical size, a CD's functionality relies on precise engineering. A CD works by focusing a 780 nanometer wavelength semiconductor laser onto a single track of the disc. This laser reads microscopic pits and lands on the disc's surface, which represent the digital data (audio or otherwise).
These consistent measurements ensure compatibility across various CD players and drives globally, making the CD a universally recognized medium for entertainment and data storage for decades.
