SD (Secure Digital) cards come in various formats, each with different capacities and capabilities. The main differences between SD, SDHC (Secure Digital High Capacity), and SDXC (Secure Digital eXtended Capacity) cards lie in their storage capacities and file system formats.

SD (Secure Digital):

• SD cards have a maximum storage capacity of 2GB.
• They typically use the FAT16 file system.
• They are the oldest and least common type of SD card now, as they have limited storage capacity compared to newer formats.

SDHC (Secure Digital High Capacity):

• SDHC cards have a storage capacity ranging from 4GB to 32GB.
• They use the FAT32 file system.
• SDHC cards are backward compatible with SD slots, but older devices that only support SD might not recognize SDHC cards.

SDXC (Secure Digital eXtended Capacity):

• SDXC cards have a storage capacity ranging from 32GB to 2TB (theoretical maximum).
• They use the exFAT (Extended File Allocation Table) file system, which supports larger file sizes and allows for greater capacities.
• SDXC cards may not be compatible with older devices that only support SD or SDHC, although many newer devices are designed to support them.