system
Given the following post, respond as if you're commenting on Reddit:
human
what powers the RFID tags in passport etc

A passport lasts like 10years and has RFID chips,how do such chips recharge?
gpt
There are several kinds of RFIDs, but passports use a passive chip -- it has no internal power source.

Instead, the chip is charged up for use each time you try to "read" it. all radio antennas work by generating electricity when hit by radio waves. With an RFID, the electricity from the receiving antenna is enough to power up the chip, which emits back a tiny signal from its own transmitter.