The primary difference between microSD and microSDHC cards is that microSD cards are limited to a storage size of two gigabytes, while microSDHC cards may have a storage capacity of up to 32 gigabytes. The added HC in microSDHC stands for high capacity. Older devices containing a microSD port, however, are not always compatible with microSDHC technology.
MicroSD cards are miniature, about the size of a fingernail, digital storage devices. They are a type of flash memory and contain no moving parts, making them very durable if cared for properly. MicroSD and MicroSDHC cards are most commonly used in mobile electronics, such as cell phones and tablets.
The SD in microSD and microSDHC stands for secure digital, which indicates the type of technology used in these cards. Secure digital standards were developed by the SD association in an attempt to establish reliable, efficient and standardized flash memory technology. Hundreds of technology companies around the world have adopted SD standards for their products.
In addition to microSD, secure digital cards come in standard and mini formats. Standard-size SD cards are commonly used in cameras, and miniSD cards were developed for mobile phones but have largely been replaced by microSD cards. In 2009, Secure Digital introduced standards for microSDXC cards, which stands for extended capacity. These cards can store up to two terabytes of data.