Symbols on SD (Secure Digital) cards

SD (Secure Digital) cards are small, portable storage devices used to store data, including photos, videos, music, and documents. Different types of SD cards are available, each with its own set of symbols that indicate its specific features and capabilities. In this article, we will explore the symbols found on different types of SD cards and what they mean.

SD Card Capacity Symbols

The capacity of an SD card is the amount of data it can store. Here are the symbols you will see on SD cards, along with their corresponding storage capacity:

1. SD (Secure Digital) - This is the original type of SD card and has a maximum capacity of 2GB. It is not commonly used anymore due to its limited storage capacity.
2. SDHC (Secure Digital High Capacity) - SDHC cards have a maximum capacity of 32GB and use the FAT32 file system. They are commonly used in digital cameras, camcorders, and other portable devices.
3. SDXC (Secure Digital Extended Capacity) - SDXC cards have a maximum capacity of 2TB and use the exFAT file system. They are commonly used in high-end digital cameras and camcorders.
4. SDUC (Secure Digital Ultra Capacity) - SDUC cards have a maximum capacity of 128TB and use the exFAT file system. They are not widely available yet, and their compatibility with devices may be limited.
5. microSD - microSD cards are smaller versions of SD cards and are commonly used in smartphones, tablets, and other portable devices. They have the same storage capacities as their larger counterparts, but their physical size is smaller.
6. miniSD - miniSD cards are larger than microSD cards but smaller than regular SD cards. They have a maximum capacity of 4GB and are not commonly used anymore.
7. SDIO (Secure Digital Input/Output) - SDIO cards have built-in input/output functions, such as Bluetooth, Wi-Fi, or GPS. They are used in devices that require wireless connectivity or location tracking, such as smartphones and tablets.
8. Eye-Fi - Eye-Fi cards are a type of SD card with built-in Wi-Fi capabilities, allowing them to transfer photos and videos wirelessly to a computer or mobile device.It's essential to check the capacity symbol on an SD card before purchasing it to ensure that it is compatible with your device. For example, if your device only supports SDHC cards, you won't be able to use an SDXC or SDUC card.

SD Card Speed Class Symbols

The speed class of an SD card indicates its read and write speeds, which determine how quickly it can transfer data to and from the card. Here are the symbols you will see on SD cards, along with their corresponding speed classes:

1. Class 2 - minimum write speed of 2 MB/s
2. Class 4 - minimum write speed of 4 MB/s
3. Class 6 - minimum write speed of 6 MB/s
4. Class 10 - minimum write speed of 10 MB/s
5. UHS (Ultra High-Speed) Speed Class 1 (U1) - minimum write speed of 10 MB/s
6. UHS Speed Class 3 (U3) - minimum write speed of 30 MB/s

The speed class symbol is essential when purchasing an SD card for use in a device that requires high-speed data transfer, such as a camera or camcorder. If the speed of the SD card is too slow, it can cause delays and buffer overflows while capturing high-resolution photos and videos.

SD Card Video Speed Class Symbols

In addition to the standard speed class symbols, there are video speed class symbols that indicate the card's ability to handle high-resolution video recording. Here are the symbols you will see on SD cards, along with their corresponding video speed classes:

1. V6 - minimum write speed of 6 MB/s
2. V10 - minimum write speed of 10 MB/s
3. V30 - minimum write speed of 30 MB/s
4. V60 - minimum write speed of 60 MB/s
5. V90 - minimum write speed of 90 MB/s

The video speed class symbol is essential when purchasing an SD card for use in a camera or camcorder that records high-resolution video. If the card's speed is too slow, it can cause the video to stutter or drop frames.

In addition to the capacity and speed class symbols, there are other symbols that you might come across when looking at SD cards. Here are some of them:

1. SDXC UHS-II - This symbol indicates that the SD card uses the UHS-II interface, which supports higher transfer speeds than the standard UHS-I interface. This is only relevant for SDXC cards with a capacity of 64GB or higher.
2. A1 - This symbol indicates that the SD card meets the Application Performance Class 1 (A1) standard, which means it can handle random read and write operations required by mobile apps. This is important if you plan to use the SD card to store apps or app data.
3. UHS Speed Class 2 (U2) - This symbol indicates that the SD card has a minimum write speed of 2 MB/s and is designed for recording high-bitrate video, such as 4K video.
4. VSC - This symbol stands for Video Speed Class, which is another standard for video recording. VSC cards have a minimum sustained write speed for video recording and playback.
5. X-Ray Proof - This symbol indicates that the SD card can resist damage from airport X-ray machines, which can potentially corrupt the data on the card.
6. Waterproof - This symbol indicates that the SD card is waterproof and can be submerged in water for a certain amount of time without being damaged.
7. Temperature Resistant - This symbol indicates that the SD card can withstand extreme temperatures, either high or low.

It's important to note that not all SD cards will have these symbols, and some manufacturers may use different symbols to indicate the same features. It's always a good idea to consult the manufacturer's website or product specifications to fully understand the capabilities of the SD card you are purchasing.

Conclusion

SD cards come in different types and capacities, and it's essential to understand the symbols on the card to ensure that it is compatible with your device and meets your needs. Capacity symbols indicate how much data the card can store, while speed class symbols indicate how quickly it can transfer data to and from the card. Video speed class symbols indicate the card's ability to handle high-resolution video recording. With this knowledge, you can make an informed decision when purchasing an SD card for your device.