SD stands for “Secure Digital”, a compact memory card format that has been designed to expand the capabilities of all types of portable devices such as digital cameras, smartphones and laptops. The original format, called MMC, has been evolving and changing, so today there are several types of SD cards that must be known to know which is the one that best suits the needs of each user.
The type of SD memory cards is defined by a series of acronyms that accompany the name, so that in order to know which card is most suitable for the needs of each user, in addition to the memory capacity of the card, it is also necessary to You need to know what type of card it is.
Usually, when buying an SD memory card, the user does not usually look beyond its capacity. That is, we want a 32 gb SD card or a 64 gb micro SD card or even we just think we want a mobile memory card. However, we tend to forget many important features such as its size, which will influence the type of card reader you will need, the writing speed or the type of memory format.
To begin to understand the different types and classes of SD cards, we will start with the size of the memory card, since this is a differentiating factor for its use.
Types of SD cards by size
One of the main factors that should be known when buying a memory card is the size and thickness of the cards. In this sense, many devices support the standard large SD format, while others only support micro SD or mini SD cards.
SD Cards: This is the original standard, measuring 32 x 24mm and 2.1mm thick. These are the cards that are commonly used by digital cameras like the positively reviewed Canon Powershot sx540.
microSD cards: They are the cards most used by modern mobile devices, they have a size of 15 x 11 mm and a thickness of 1 mm.
miniSD cards: This is a format little used in devices, it has a size of 21.5 x 20 mm and a thickness of 1.4 mm.
Also, most memory cards on the market are sold with adapters that allow you to convert a micro SD card to an SD card. These adapters offer great versatility to users, to change devices without having to buy a different size card.
Card types according to storage capacity
On some occasions, when buying a card, we find some codes that accompany the name of the card. These codes indicate the maximum storage capacity that the cards have. In this sense, you can find:
SDXC card : The acronym XC translates as “Extended Capacity”, which means that they have a larger size, and can reach 2TB, which is about 2000 GB. These types of acronyms are what you will find when you buy, for example, a 128 gb micro SD card.
SDHC card : HC means “High Capacity”, that is to say that they are high capacity cards and have a maximum capacity of 32 GB.
SDSC card: They are the original memory cards, in fact SC means “Standard Capacity”, that is, standard capacity, since they have a maximum capacity of 2 GB, so they have fallen into disuse.
Memory cards are backward compatible, meaning that if your device is compatible with SDXC cards, you can use any inferior card without any problem. However, since this is just backwards compatibility, on devices that support low-capacity cards you won’t be able to use larger ones. In this sense, most devices indicate the maximum memory they can support, so it is advisable to look carefully at this point before buying.
Types of cards by class
The class of the card indicates to the user the writing speed available to it. In this sense, there are Class 2, Class 4, Class 6 and Class 10 cards, whose name indicates the writing speed in MB/s they offer. In addition, there are the UHS Speed Class 1 and UHS Speed Class 3 classes, which have an Ultra High Speed Bus, so they have a different name from the first.
Class 2 SD card: It has a minimum speed of 2 MBps and is used for photography and video in low resolution.
Class 4 SD Card : With a minimum write speed of 4 MBps, it allows you to record videos in 720p and HD.
Class 6 SD Card: Features a minimum write speed of 6 MBps and is used for 720p and HD video.
Class 10 SD Card: Offers a minimum write speed of 10 MBps and is optimal for high-speed photos and Full HD 1080p videos.
UHS Speed Class 1 (U1): With a minimum speed of 10 MBps, but a higher Memory Bus to record FullHD videos at 1080p.
UHS Speed Class 3 (U3): It has a minimum writing speed of 30 Mbps and is capable of recording 4K videos.
In addition, there is another SD quality that would be Class V and that is intended for memory cards dedicated exclusively to video recording.
Finally, when buying a card, it is also necessary to look at the side tab, which is the write protection and allows you to block the card so that no more data can be recorded on it. This mechanism prevents data from being accidentally deleted.
Some SD cards also have a WiFi connection and are useful for transferring files from a mobile device to a computer, without having to connect the devices to each other.
With all this information, it is possible to choose the most suitable micro SD memory card for the needs of each user.