How Retail Anti-Theft Tags Use Magnetostriction
Applied Science · Explainer · 16 min · 2015 · YouTube title: How anti-theft tags work - magnetostriction
Why it's here
HN recommends it as an informative explanation of what those tags are, especially in threads about implants and RFID.
What it covers
Applied Science explains how retail anti-theft tags work. A tiny magnetostrictive strip acts as a mechanical oscillator excited by a magnetic field, and magnetizing or demagnetizing it arms or disarms the tag.