SD memory cards work by recording data onto a solid-state chip inside the card using flash memory. The flash memory records information when electrical charges change in its circuits. A similar process erases portions of the memory for rewriting.
SD is an abbreviation for "secure digital." The data on an SD card is stored in a digital format. The solid-state chip inside the card's plastic cover contains many tiny electrical circuits. When the card is not in use, the circuits retain their charges without any additional power. When a card is placed in an activated device, such as a camera or a cellphone, a small electrical current from the device moves electrons in the flash memory chip. The digital patterns stored on the chip correlate to the data stored there. Data is erased when a slightly higher voltage is applied to the circuit. This allows for rewriting. SD cards write and erase memory in blocks or sections. This makes them faster than some other varieties of data storage.
SD cards meet legal requirements for storing content with copyright protection. Copyright protected works, such as songs and books, are written with a media identifier code. That code is placed on a protected portion of the solid-state memory. The copyright protected work cannot be copied without access to that media identifier code. This keeps data from being copied multiple times and widely circulated without permission.Learn More
Flash memory cards consist of large numbers of individual cells, each of which contains a set of transistors. Under normal circumstances, current flows between the transistors and into a drain. When a charge is applied to one of the transistors, the current flow gets blocked. The amount of current passing through the cell effectively flips it from a one to zero, allowing for the storage of binary data.Full Answer >
An SD card, also known as a Secure Digital Memory Card, is a small data storage device used in cell phones, digital cameras and other mobile electronics. They are popular due to their fast rate of memory storage. The term SD card encompasses a few different types of cards.Full Answer >
To format an SD card, connect the SD card to your computer. After backing up the data on the SD card, use the built-in formatting utility on the Windows operating system to format the card.Full Answer >
According to technology review site The Wirecutter, the best brand of SD memory card is SanDisk, as of 2014. The site recommends SanDisk's 32-gigabyte Extreme Plus SD card as the best choice for most users.Full Answer >