A DVD is a device that allows access to the information stored on a CD or disk, as well as USB and other connections, in order to see its audio and video content.
For the most part, DVDs require connection to an output device such as a television, and there is also one type of these that are portable, that is, they have a portable screen. The key parts of a disc are: a motor, a laser and lens system, and a tracking system.
The acronym DVD stands for Digital Versatile Disco. In addition, it refers to the various ways in which data can be stored, for example: DVD-R, DVD + R, DVD-ROM (read-only), DVD + RW, DVD-RW (allows it to be burned and then data is deleted). They also refer to the capacity of each of them to store. The emergence of the DVD standard occurred in 1995, called the Consortium (DVD Consortium).
DVDs are divided into two categories, through which it is possible to determine the capacity of the disc, these are: single layer and double layer. The disc may also have one or two sides, as well as one or two layers of data on each side.
Single-layer DVDs have room to store up to 4.7 gigabytes on a decimal basis and about 4.38 gigabytes on a binary basis, which is about seven times more than a standard CD. Double-sided DVD formats are hardly used outside the scope of DVD-Video.
The fundamental parts of a DVD
The laser and lens system that allows focusing on the storage units and makes reading possible.
The wavelength of light of this laser is 640 nanometers, which is less than that of a CD player, whose length is 780 nanometers, which makes it easier for the DVD laser to focus on the parts that are smaller in the disc.
The tracking mechanism, thanks to this it is possible to move the laser device, allowing this to follow the spiral of the track. It is a system that must have the capacity to move the laser to a resolution that is millimeter.
The motor, so that the turning of the disk is possible. This is finely tuned to allow you to rotate between 200 and 500 revolutions per minute, depending on the track you are currently reading.
External parts of the DVD
- Tray and Cover: it is the one that makes possible the support of the disc and the proper placement of it so that it can be read by the internal laser.
- Mode selector: it is in charge of establishing if a certain unit is going to act as master or slave.
- Eject button: is the one that gives way to the manual eject of the cover to eject and put another disc.
- Cover: is the one that provides protection to the internal mechanism and all the circuits that compose it.
- 4-terminal connector: is responsible for receiving power.
- 40-pin connector: enables the interconnection with the motherboard or main card via the IDE cable.
- S / PDIF connector: This is used to connect the cable for the digital signal.
- Indicator: an LED that lights up when the unit is running.
- Speed: A DVD has a given data transfer rate in multiples of 1350 KB / s.