Micro SD cards are one of the smallest removable flash memory card formats specifically designed for small devices, mainly used as phone memory. Smaller than mini cards, and also based on the format of the SD card, micro cards are approximately 15mm x 11mm in size, roughly the size of your little finger nail. Older devices only support Micro SD cards, while newer devices support both Micro SD cards and Micro SDHC cards.
Micro can also be used in SD compatible devices via SD adapter. Micro SD cards are becoming more and more popular because they are so small and thin and mobile phones and MP4 video players are increasingly using this innovative space saving technology.
Speeds
The speed of a Micro SD card is measured by how fast information can be read or written to the card. You can store higher definition videos, higher resolution photos and you don’t have to worry about losing your precious data. In applications that require sustained write performance, such as video recording, the device may not perform satisfactorily if the class rating of the card falls below a particular speed.
On early cards, speed was measured by the “×” rating, which compared the average data reading speed to that of the original CD-ROM drive. Currently, the official unit of measure is Speed Class Rating, which guarantees a minimum speed at which data can be written to the card.
New SD card families improve card speed by increasing bus speed. Whatever the bus rate, the card can tell the host that it is “busy” until a read or write operation completes. Meeting a higher speed rating is a guarantee that the card limits the use of the “busy” indication.
Different kinds of speed
The speed class classification is the official unit of speed measurement. The class number guarantees a minimum write speed as a multiple of 8 Mbit / s (1 MB / s)
These are the ratings of all the cards currently available:
Class 2: 2MB / s speed
Class 4: 4 MB / s speed
Class 6: 6MB / s speed
Class 10: 10 MB / s Speed
Common applications for speed classes
Class 2: H.264 video recording, MPEG-4, MPEG-2 video recording
Class 4: MEPG-2 Video Recording (HDTV), Shooting Consecutive Still Digital Camera (DSC)
Class 6: Consecutive Shooting Megapixel DSC, Professional Video Camera
Class 10: Full HD video recording, HD still image consecutive capture
