Sunday, 25 September 2011

RFID, What is RFID

From Wikipedia
Radio-frequency identification (RFID) is a technology with components that are not a replacement for the barcoding, but a complement for distant reading of codes. The technology is used for automatically identifying a package or an item. To do this, it relies on RFID tags. These are small transponders (combined radio receiver and transmitter) that will transmit identity information over a short distance, when they are asked to. The other piece to make use of RFID tags is an RFID tag reader.
An RFID tag is an object that can be applied to or incorporated into a product, animal, or person for the purpose of identification and tracking using radio waves. Some tags can be read from several meters away and beyond the line of sight of the reader. Most tags carry a plain text inscription and a barcode as complements for direct reading and for cases of any failure of radio frequency electronics.
Most RFID tags contain at least two parts. One is an integrated circuit for storing and processing information, modulating and de-modulating a radio-frequency (RF) signal, and other specialized functions. The second is an antenna for receiving and transmitting the signal.
There are generally two types of RFID tags: active RFID tags, which contain a battery, and passive RFID tags, which have no battery.


RFID systems are used for the following:
  • General transport (logistics), tracking a packageparcel; replacing barcodes
  • Tracking vehicles for road toll
  • Many countries have started using RFID chips in passports
  • Making products harder to falsify; currently proposed for drugs
  • Tags in clothing, eg. in Jeans
  • Sealing for containers (for the shipping industry). Not required yet.
  • Identifying animals; used for tracking pets, but also for research, for example on turtles.
  • Keys for vehicles. The vehicle key has an RFID tag inside; only the key with the right RFID tag can start the vehicle (this makes copying vehicle keys harder). Also used for locking/unlocking vehicles from a distance.
  • Contactless identity cards, for example to regulate entry into certain areas; also used for ticketing, or public transport

3D Printer

3D printer is a computer output device that can make solid copies of objects from computer drawings. There are a number of different types. All of these work in different ways. Some use powder. Some use liquid plastic. They all make the object by building it up layer by layer.
In some industries these printers are called rapid protoyping machines




From Wikipedia, the free encyclopedia

In information technologies we use the term DDR2 SDRAM for a Double Data Rate memory module of the second generation. Thistechnology is used for high speed storage of the working data.


The main difference between DDR and DDR2 modules is that the bus on which the DDR2 memory modules are working is clocked at twice the speed of the memory cells. In practical terms we can say that four words of data can be transferred during one memory cell cycle. To sum it up DDR2 can effectively operate at twice the bus speed of DDR.

Specification standards

Chips and modules

For use in PCs, DDR2 SDRAM is supplied in DIMMs with 240 pins and a single locating notch. DIMMs are identified by their peak transfer capacity (often called bandwidth).
Standard nameMemory clockCycle timeI/O Bus clockData transfers per secondModule namePeak transfer rate
DDR2-400100 MHz10 ns200 MHz400 MillionPC2-32003200 MB/s
DDR2-533133 MHz7.5 ns266 MHz533 MillionPC2-42004266 MB/s
DDR2-667166 MHz6 ns333 MHz667 MillionPC2-53005333 MB/s
DDR2-800200 MHz5 ns400 MHz800 MillionPC2-64006400 MB/s
DDR2-1066266 MHz3.75 ns533 MHz1066 MillionPC2-85008533 MB/s

Introduction to PC Hardware, Computer hardware

Computer hardware or hardware means the fixed parts that make up a computer.
Some examples include:
Hardware needs software to tell it what to do. Without software, the hardware can not be used.

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