Below, the author briefly introduces seven kinds of memory cards widely used in mobile phones, hoping to provide some help for you to buy mobile phone memory cards.
Introduction of mainstream mobile phone memory card type SD card: SD card is a memory card based on semiconductor flash memory. The standard volume is 24 mm *32 mm *2. 1 mm, and the weight is only 2 grams.
SD card has the advantages of large capacity, fast data transmission speed and strong security (anti-write lock function). SD card is widely used and has now become the memory card with the highest market share.
MiniSD card: As the name implies, MiniSD card is a small memory card that is "slimmed down" on the basis of SD card. It can be converted into an SD card through a special adapter and miniSD card.
It should be pointed out that the miniSD card does not have the anti-write lock function like the SD card. MiniSD card is mainly used for windows mobile and S60 third edition smartphones.
MMC card: MMC card is an old memory card and compatible with SD card devices. MMC can be used normally for most mobile phones with SD card models. The overall size is about 32 mm *24 mm * 1.4 mm, which is the same as that of ordinary stamps.
The weight does not exceed 2 grams, and the portability is strong. The working voltage of MMC card is divided into 1.8 volts and 3.6 volts, which should be paid attention to when purchasing.
The transmission speed of MMC card is relatively slow, and MMC card is rarely used in new mobile phones. MicroSD card: MicroSD card, also known as TF card, is also a new memory card improved from SD card.
Only a quarter of the size of the SD card, it is the smallest memory card at present. Due to its small size, the maximum capacity of microSD card is limited.
Some memory cards have reached the capacity of 8GB, while the microSD card with the largest capacity on the market is only 2GB. In addition, the microSD card has a built-in copyright protection management system, which can effectively curb malicious resources.
RS-MMC card: RS-MMC card can also be called MMCmobile card, which is a small MMC card developed for mobile phones. RS-MMC card supports dual-voltage operation and has better compatibility than MMC card.
It is superior to MMC card in transmission speed and stability, and is mainly used for Nokia's S60 second edition smartphone. MS card: MS card, commonly known as memory stick, is a memory card developed by Sony.
Divided into long sticks and short sticks, short sticks can be transformed into long sticks with adapters. At present, MS cards used in mobile phones are all short sticks, which are special for Sony Ericsson mobile phones.
MS card has fast reading and writing speed, high reliability and dustproof. M2 card: M2 card is an improved version of MS card, smaller in size, and more suitable as a new generation of mobile phone memory card.
The size of M2 card is only a quarter of that of MS card, which improves the security and transmission speed, and supports dual-voltage operation, with lower power consumption than MS card. Choice of mobile phone memory card: First, confirm what kind of memory card to buy.
What kind of memory cards are supported will be indicated in the mobile phone manual. Please read the memory cards before buying them. If your mobile phone supports more than two kinds of memory cards, you should choose the fastest and most stable memory card.
Take Motorola E680i as an example. Although SD card and MMC card are supported at the same time, considering that SD card is superior to MMC card in transmission speed and stability, it should be purchased. In addition, if your mobile phone has requirements for the working voltage of the memory card, you should look at the relevant labels on the memory card package when choosing the memory card to avoid buying a memory card that is incompatible with the mobile phone.
Secondly, try to choose memory cards of famous brands. The demand for memory cards is strong, which leads to a large number of inferior memory cards with inferior brands entering the market.
Although this kind of inferior memory card is cheap, it is unstable and has a short service life, and may even seriously damage the mobile phone. When choosing a memory card, netizens must choose a memory card of a well-known brand (SanDisk/Sony /Kingmax, etc.). ), and don't buy inferior memory cards with inferior brands for cheap prices.
Once again, keep your eyes open and refuse fakes. At present, there are many counterfeit memory cards on the market.
This kind of memory card looks like a famous brand, but it is actually an inferior product produced by some small workshops. So how to identify counterfeit memory cards? There are three main points. First, pay attention to packaging and workmanship.
The packaging and workmanship of counterfeit memory cards are relatively rough, which is obviously not as good as genuine memory cards. The second is to pay attention to anti-counterfeiting labels.
Memory cards of well-known brands are generally printed with anti-counterfeiting labels with authentication phone numbers and identification codes. You can call the authentication phone number to verify the authenticity. The third is to look at the price.
The price of counterfeit memory cards is generally more than half cheaper than the genuine ones.
2. The actual capacity of the memory card
You know, the unit conversion of all physical equipment is different from the theoretical conversion we studied.
Theoretically 1M= 1024KB.
However, the conversion methods on physical devices are different. Physically, 1M= 1000KB, so your 5 12MB memory card =5 12000KB, and the computer is identified by 1MB= 1024KB. So your USB flash drive is very small. But because of the different manufacturing processes, the storage devices will be more or less different. If you don't believe me, you can buy another USB flash drive with the same size, and you will find that the storage capacity is different from yours. It's like you bought "Joy" and said it was 200 grams, but you got it right, but there is still a discrepancy.
Not only USB flash drives, hard disks, mobile hard disks, MP3 and other hardware devices are calculated according to 1MB= 1000KB.
3. Basic knowledge of mobile phone memory card
Micro SD card, formerly known as Trans-flash Card(TF card), was officially renamed as Micro SD card in 2004 and was invented by SanDisk Company. Before the launch of Micro SD, mobile phone manufacturers used embedded memory. Although the installation of this module is simple, there is a trouble that it cannot meet the actual trend demand-the capacity is limited and there is no room for upgrading. Micro SD imitates the application mode of SIM card, that is, the same card can be used on different types of mobile phones, so that mobile phone manufacturers do not have to worry about plug-in R&D design. Micro SD card is enough to make a portable storage IC.
Micro SD card is a very small flash card, and its format originated from the creation of SanDisk. Originally, this memory card was called T-Flash, and later it was renamed Trans Flash. It was renamed micro SD because it was adopted by SD Association (SDA). Other memory cards used in SDA include Mini SD and SD card. It is mainly used in mobile phones, but because of its small size and increasing storage capacity, it is used in GPS devices, portable music players and some flash drives. Its volume is15mm x11mm x1mm, which is almost the size of a fingernail. It is the smallest memory card at present. You can also connect to the SD card slot through the SD adapter card. At present, MicroSD cards provide 128MB, 256MB, 5 12MB, 1G, 2G, 8G, 16G, 32G, 64G, 128G (mwc20/kloc-0
4. Why has the space capacity of my memory card become smaller?
First of all, memory cards also have a lifetime. Excluding man-made damage, the capacity of the memory card will be less and less.
Furthermore, memory cards use storage media to store information, which will be worn out in the process of reading and writing information repeatedly. Information is scanned every time it is read and overwritten every time it is written. Reading, such as ordinary copying; Writing is to create a new file and then save useful information in the file or paste a file. Basically, reading and writing mobile phones will generate a lot of heat, because electric energy is converted into heat energy. Although the medium is tough, it is a cumulative effect with more heating times, so the temperature also has a gradual effect on the medium. Therefore, the files in the storage area of the memory card area will be damaged more and more with the increase of usage times, that is, the capacity will be less and less.