Types of RFID
The types of RFID tags can be narrowed down to two general varieties, powered tags (active) and non-powered tags (passive). Although there are other sub-varieties in operation (see http://en.wikipedia.org/wiki/RFID)
- Passive RFID tags do not contain a battery. When the tag comes in range of a scanner power is drawn to the tag, and in return the tag sends its memory contents to the scanner. Because the tags can not omit a signal the reading distances are greatly reduced, around 50cm max.
- Active RFID tags do contain a battery, it allows the tag to transmit a part or even the entire tags signal to the scanner. This allows the tag to transmit to distances of up to 30 metres or more, significantly improving the applications for the device.