Expand Your NOOK eReader with a microSD or microSDHC Card
The microSD or microSDHC card used in your NOOK eReader can store as much reading material as you could possibly need — up to approximately 32,000 average-size books or millions of pages of documents from your personal computer.
When you shop for a memory card, make sure you purchase a microSD (Secure Digital) or microSDHC (Secure Digital High-Capacity) card. Do not purchase a regular SD or SDHC (or the rarely-seen miniSD card, which is not in common use). Only micros need apply; the others simply will not fit.
SD is a form of non-volatile memory; that means once data is recorded to it, that information will remain in place even when the power is turned off. It requires a pulse of voltage to write information and another pulse to erase or change it.
microSDHC cards are rated by Speed Class, a measurement of how fast they can read and write data. That’s important for devices like digital cameras and music or video players. Since eReaders are by nature relatively slow devices, the Class rating of an SDHC card is not relevant.
microSD cards are available in capacities up to 4GB. microSDHC cards begin at 4GB and can hold as much as 32GB. 32GB is a lot of space. It could hold approximately 32,000 average-size books, plus the ones stored in the internal memory of the NOOK. That should be more than enough reading material for a week’s vacation by the sea. . . and probably sufficient for a roundtrip spaceflight to Mars or the waiting room at the DMV.
But if you want to think of it in other terms, imagine you're a mechanical engineer and you want to travel with every possible reference book you might need for a project. Or you’re a professor of English Literature and it is critical that you have at hand any one of perhaps 32,000 great books in case you need to cite chapter and verse. One microSDHC card should be all you need.
Prices of this sort of memory have dropped greatly in recent years as they have become commonly used in devices such as smartphones and digital cameras. Although the cards rarely fail, spend just a few dollars more and purchase from a company whose name you recognize; they are more likely to offer a quality product and a warranty. These established companies include Kingston, Kodak, Lexar, Samsung, and Sandisk.
You do not need to pay more for a faster class of card; buy based on the capacity you want, not the speed. The NOOK can work with Class 2, 4, or 6 cards; there is no reason to pay extra for a Class 8 or 10 card.
For more information about the NOOK eReader and its features, explore NOOK eReaders For Dummies, Portable Edition.