Secure Digital card facts for kids

An SDHC card, which is a type of memory card. This one can hold 8 gigabytes of data and has a speed rating of Class 6, meaning it can write at least 6 megabytes per second.

A Secure Digital card, usually called an SD card, is a small memory card. Think of it like a tiny digital storage box! People often use SD cards to save pictures and other data in devices like digital cameras, smartphones, and even some video game consoles.

SD cards are shaped like a small rectangle, but one corner is cut off. This clever design makes sure you always put the card into your device the right way, so it doesn't get damaged.

What Kinds of SD Cards Are There?

SD cards come in different types, mainly based on how much information they can hold:

• SD cards: These are the original type and can store up to 2 GB of data.
• SDHC cards: These are "High Capacity" cards. They can store more, from 4 GB up to 32 GB.
• SDXC cards: These are "eXtended Capacity" cards. They can hold a huge amount of data, up to 2 TB! (Currently, the largest ones you might find are around 512 GB).

It's important to know that older devices that only work with original SD cards might not be able to use SDHC or SDXC cards. However, devices that can use SDHC cards can usually also use the older SD cards. SDXC cards use a slightly different way of organizing data, called a file system, compared to SDHC cards. Sometimes, older devices like the Wii can be updated with new software (called firmware) to let them use SDHC cards.

How Fast Are SD Cards?

SD cards also have different "classes" or speed ratings. These tell you how fast the card can save or read information. It's like how fast a car can drive!

• Class 2: This means the card can write data at a minimum speed of 2 MB per second.
• Class 4: This means at least 4 MB per second.
• Class 6: This means at least 6 MB per second.

Sometimes, different companies measure these speeds in slightly different ways. Some might tell you the fastest speed the card can reach, while others guarantee a minimum speed.

Another way to measure speed is called "rating." A rating of 1 is like the speed of an old CD, which is about 150 KB per second. So, a Class 2 SD card is about 13 times faster than that!

What About Smaller SD Cards?

You might also see microSD cards. These do the same job as regular SD cards but are much, much smaller. They are often used in smartphones and other tiny gadgets.

Images for kids

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  A microSD card inside a smartphone.

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  This tiny microSDHC card holds 8 billion bytes! Below it is an old magnetic-core memory from the 1970s that holds only eight bytes.

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  The back of a Lexar UHS-II microSDHC card, showing extra connections for faster speeds.

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  The front and back of an SD Express card, designed for very high speeds.

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  A 64GB SanDisk Ultra microSDXC card, showing its speed markings.

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  A 32GB Lexar 1000x microSDHC card, with its speed markings.

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  The front and back of a Sony 64GB SF-M Tough Series UHS-II SDXC Memory Card.

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  This Sony 64GB SF-M Tough Series UHS-II SDXC Memory Card is special because it doesn't have a sliding tab to protect against accidental writing.

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  From left to right: An adapter to use a microSD card in a regular SD slot, an adapter for a miniSD slot, and a microSD card itself.

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  SD cards that can also plug directly into a USB port.

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  A camera that uses an SDIO interface to connect to some HP iPAQ devices.

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  On the left, a real Samsung Pro 64 GB microSDXC card. On the right, a fake one that claims to be 64 GB but only holds 8 GB.

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  Pictures of real, questionable, and fake microSD cards, showing what's inside them.

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  An SD card being inserted into a DSLR camera.

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  A special board that lets Arduino microprocessors use SD cards.

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  Size comparison of different SD card families: SD (blue), miniSD (green), and microSD (red).

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  This image shows the official pin numbers for different types of memory cards, from older to newer.

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  What's inside a 512 MB SD card: the NAND flash chip that stores data (bottom) and the SD controller chip (top).

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  Inside a 2 GB SD card: two NAND flash chips (top and middle) and the SD controller chip (bottom).

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  The inside of a 16 GB SDHC card.

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  A 4 GB SDSC card.

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  A disassembled microSD to SD adapter, showing how the smaller card connects to the larger pins.

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  A size comparison of different types of flash memory cards, including SD, CompactFlash, MMC, and xD.

See also

In Spanish: Secure Digital para niños