What is the difference between passive and active NFC devices ?

Passive NFC tags have no battery or power source. They only get their energy from the proximity of the reader. Active NFC tags have their own battery or power source.

All the NFC tags we sell are passive. The 'antenna' on an NFC tag is actually an inductor and energy is generated from the reader using electromagnetic fields. When passive tags are not powered by the reader, they cannot do anything - they cannot emit a signal, monitor status or anything else. A substantial benefit of passive tags is that they don't 'run out'. Some NFC tags have 50 year memory lifespans and can be scanned for generations to come !

Active tags have a power source such as a battery. Typically, this is a card reader in a store for taking payments or perhaps a gate at a subway or train station. These can be more powerful and scan distances can be longer. For smaller active devices with a battery, these can be for interim monitoring applications. For example a small active tag can monitor temperature at intervals between scans. Clearly, in these cases, the battery will eventually expire and the tag will no longer be useful.

Seritag - 28 Nov 2024