system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How are RFID tags read with antennas and readers, and how is the information sent back and analysed by a computer?
gpt
An RFID tag is really two parts - a small chip and an antenna.

When a reader scans the tag, it supplies a small amount of power over the air.  The antenna picks up that power and it is _just_ enough to activate the chip.  The chip then broadcasts a message, which the reader receives and stores.  It then takes that message and compares it to a database to achieve the desired output, be that firing a command, pulling up a record, etc.