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How anti-theft tags work - magnetostriction

Applied Science · 886.5K views · 2015-11-30 · 15:41

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Overview

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.

On Hacker News

HN recommends it as an informative explanation of what those tags are, especially in threads about implants and RFID.

Recommended by 1 HN people across 1 months · HN mentions 2017–2020

Topics

Everyday physics & science demosFundamental physics
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magnetostrictionanti-theft tagsphysicseasapplied science

What people said

wolfgang42 · 2017-07 · Recommendation

Right, which is precisely why automatic doors are completely irrelevant. On a related note, here's an interesting and informative video from Applied Science on how these tags work: [VIDEO]

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aftbit · 2020-12 · Reference

Those RFID tags are pretty minimal though. Basically just a thin trace antenna and silicon die directly molded into plastic. [VIDEO] I still agree that it's amazing that our society can make functional structures with feature sizes in the nm/µm ranges so cheaply that we can afford to throw them away.

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sannee · 2018-11 · Reference

Are you sure these tags are RFID? I have only ever seen magnetostrictive tags [1] (but I don't buy expensive clothing...). [1] - [VIDEO]

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Sources

Video by Applied Science, played through YouTube.

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