Whats the difference between active and passive RFID tags?
Active tags contain a power source, usually a battery. They are always on, emitting a signal periodically. Semi-active tags hibernate until woken up by a reader. Then, they power up and emit their signals for a defined period of time. Passive tags, on the other hand, do not have a power source and rely on the incoming radio signal from the reader for power to send back a signal containing data. Active tags typically have a larger read range and more memory than passive tags since the power source gives more power to broadcast radio waves. In addition, many of the active tags we see coming to market today also incorporate other sensors, such as temperature or light sensors, and can communicate the sensory data along with the tag identification data. Due to their onboard power source, active tags are usually more expensive and larger in size than passive tags.
