People who use portable electronic devices often want to store their data in a portable way. This is especially true for users of mobile phones, portable global positioning system (GPS) devices, and video and audio players and recorders. One of the main formats for these portable memory sources is a microSD card, which is one of the smallest flash memory cards on the market. It’s made by SanDisk, which lends the SD to its name; the other part of the name comes from the small size of the card.
A full size SD card.
SanDisk originally made the SD card, which was slightly larger than the microSD card. Then came the miniSD card, which was slightly smaller, and the microSD card, the smallest of all. Most technical measurements for the tiny card are 15 by 11 by 1 mm (approximately 0.59 by 0.43 by 0.04 inches), which is about the size of a fingernail.
With an adapter, microSD cards can be used to store photos and videos taken with digital cameras.
The microSD card is about a quarter of the size of a standard SD card, but can still be used with devices that have SD card slots using a special adapter. Portable audio and video players have SD card slots, and some of the newer models even have smaller slots. When used in a cell phone or handheld GPS device, the card is usually embedded in the electronic device. Some cell phones or GPS trackers have removable cards, but this feature is generally reserved for devices of a different nature, that is, those that lend themselves to expandable and collapsible memory needs, such as video and audio players.
The general idea behind SD cards is that they can have variable memory capacity. A common amount of memory for one of these cards is 1 gigabyte (GB), although microSD cards are also available in capacities of 128 megabytes (MB), 256 MB, 512 MB, and 2 GB. The more data the card has, the more expensive it will be.
However, this increase in capacity does not mean a corresponding increase in physical size. The technology that allows computer hard drives to get smaller and smaller, while also being able to store more and more data, also applies to these memory cards. The 128MB microSD card looks a lot like the 2GB card, for example, but the user will notice the difference when swapping one for the other in a digital audio player.
