What Is An SD Card?

We'll tell you all you need to know about this useful item

What Is An SD Card

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Whether you are getting into photography, looking to increase the storage on your phone, or in another handheld device, then you’ll likely have encountered an SD card. But understanding what it is and how it operates within a device can help you learn more about electronics, how they are used and how they function.

What Is An SD Card

What Does An SD Card Do?

SD card stands for Secured Digital card – a type of storage that is a removable memory card known to read and write growing quantities of data within a mix of different electrical devices.

In many small electronic devices, the SD card had become the most popular form of memory card. This was until the advent of the micro SD card which is now used more in products like phones and other small devices.

Where Are SD Cards Commonly Used?

The small physical size of the SD card and its various upgrades, including the Micro SD card which is even smaller, means they are ideal for small electronic devices that can require extra storage to work optimally.

A camera is perhaps the most common use of the SD card, as a digital camera requires the ability to store lots of data from high quality pictures as well as the requirement for fast reading and writing of that data.

Most laptops have SD card slots built into them for this very reason, as compact digital cameras use SD cards just as a much as larger or more specialized DSLR cameras.

They are also used in devices like satnavs, ebook readers, and TVs. Smaller handheld devices like the Steam Deck or smartphones opt for the micro SD card standard.

How SD Cards Have Changed Over The Years

SD cards, like most pieces of technology, have changed over the years in terms of specification. While the SD card replaced a now obsolete piece of tech called the MMC or MultiMediaCard, it’s since diverged itself.

  • SD – This original standard SD card is actually no longer even made. It once had a maximum capacity of 2GB and utilized the FAT16 file system.
  • SDHC – The Secure Digital High Capacity can support up to 32 GB in capacity.
  • SDXC – The Secure Digital eXtended Capacity card from 2009 could store up to 2 TB
  • SDUC – It took until 2018 to create this level of SD card – the Secure Digital Ultra Capacity card can support around 128 TB of data. Astronomical in comparison to the original 2GB.

Final Thoughts

SD cards are another store of data that can be kept in or separate from a device as additional backups. Their small size makes them ideal to put in certain devices like cameras, but the Micro SD card standard is more popular for widespread use in smartphones etc. – primarily due to its size.

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Kevin has been a technophile since he first owned a Commodore 64. Then an Amiga….progressing to Gameboy, self-built systems, consoles, and a 15-year career in and around computing and technology. Kevin is an all-around tech and gadget enthusiast. He was previously found at such places as Micro Mart, Custom PC, Bit-tech, and PC PRO, then Which? Computing, Den of Geek, and Daily Telegraph. Also WIRED, Hardware Heaven, and KitGuru.

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