SD cards, short for secure digital cards, are removable, compact memory cards used for data storage in portable devices such as digital cameras. Some PCs and laptops come with an SD card slot or you can purchase a card adapter separately. The most compact of the SD card family is the Micro SD card sometimes referred to as microSD which is used in small devices such as smartphones.

What size are SD cards?

SD cards come in three different physical sizes, standard, mini and micro. The size you choose depends on which device you plan to use it in. Each SD memory card will have a capacity size in GB or MB which refers to the amount of data that can be stored on the card. Larger capacities will be more expensive so it is best to choose an SD memory card that meets your storage needs.

Why would you need an SD card?

Most devices today come with built-in memory storage to a certain capacity. However, it is very easy to use their internal memory up, and that is where SD cards are useful. They add-on to your personal device that can greatly boost the amount of media you can store at one time. You will not have to worry about having to delete important photos from your camera, or music from your smartphone. With most SBCs, including Raspberry Pi, they run their OS from an SD Card. To shop Raspberry Pi micro SD cards preloaded with NOOBS, visit our sister site OKdo for all things Raspberry Pi and SBC.

What is SDUC/SDXC/SDHC?

SDUC/ microSDUC stands for Secure Digital Ultra Capacity. This supports memory cards up to 128TB.
SDXC/ microSDXC stands for Secure Digital eXtended Capacity. SDXC cards support up to 2TB.
SDHC/ microSDHC stands for Secure Digital High Capacity. SDHC card refers to SD cards which have a higher storage capacity, usually over 4GB.

What is Speed Class?

Speed class is a standard developed by the SD association. Speed Class, UH Speed Class and Video Speed Class are given to indicate the minimum writing speed of a memory card. They include:

Speed Class - 2, 4, 6, 10
UH Speed Class - UHS-I, UHS-3
Video Speed Class - V6, V10, V30, V60, V90

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