MicroSD cards are the smallest Secure Digital cards, usually referred as SD cards. Its family consists of many types of cards including High-Capacity (SDHC), Standard Capacity (SDSC), eXtended- Capacity (SDXC) and input / output (SDIO). SD cards are also available in three different sizes i.e. original size, mini version of it (miniSD cards) and then, the micro size which is the microSD card.

MicroSD cards are the removable and non-volatile cards that are used to store your data on many devices like digital cameras, mobile phones and many others. They use flash memory to store data i.e. can retain data even in the absence of power supply. MicroSD cards were first introduced in 2005, but within a short span of time, it became the most widely used memory card format. Its size is around 15mm x 11mm x 1.0mm. Although it’s tiny in size, it provides a great format for camera settings and also has large storage capacity.  Their storage capacity ranges from 128 megabytes (MB) to 8 gigabytes (8GB) and even 32 GB in some new cards. An average 8GB microSD cards can store over 1000 pictures, 25 hours of your videos, 1000 songs and even some games.

MicroSD card Classification:

MicroSD cards are classified and rated according to their transfer rate i.e. write and read speed. Based on the minimum write speed they are identified in three different classes like Class 2, class 4, and class 6. Write speed is calculated for writing data to a new microSD cards which never had any data until now. The write speeds for these classes are as mentioned below:

  • Class 2 - Speed is 2 megabytes/second
  • Class 4 - Speed is 4 megabytes/second
  • Class 6 - Speed is 6 megabytes/second

Hence, Class 6 has the fast write speeds. Cards are also identified based on speed rating of the card itself. It is actually to know how fast the microSD card can READ the data from the card. It is described as 6x, 32x, 64 x etc. it can be any digit ending with x. This “x” stands for the relative write speed of the original CD-ROM which is 150 kb/second. Hence, 6x indicates 6 multiplied by 150 kb/sec. Hence, 6x is 0.9 kb/sec, 40x is 6 kb/s, 100x is 15 kb/s. Before purchasing the microSD cards, one needs to be aware of these classes and card speed rating, in order to pick the efficient one.

Some of the popular MicroSD card brands: Transcend Kingston, SanDisk, and Sony etc.

Uses of SD cards:

A micro SD card can be used in cellular phones, digital cameras, digital audio players, portable media players, expandable USB flash drives, newer video players, GPS devices, PDA’s and other devices. Even though the old devices or brands do not support microSD cards, nowadays almost all of the modern devices are compatible with microSD cards. Some of the brands of these devices are as mentioned below:

Camera Brands:  Vivitar Vivicam 5.1MP V5024, Sony Cyber shot DSC-W170, the 8.1MP Underwater Digital Camera and most of the Olympus cameras etc.

Cellphone brands:  HTC TYTN, LG Voyager, T-Mobile G1, BlackBerry Curve 8310 and Samsung BlackJack II and many others.

Others: Garmin Oregon 400t for GPS system and jWIN 2 GB MP3 Player, many more all support MicroSD cards

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