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From the Q&A

With TJ Byers

Don’t Bug Me!


Some years ago, I was watching a TV show on electronic espionage and counter-espionage when mention was made of a device that could detect bugs, even when they were not operating, by virtue of its ability to detect silicon junctions; in other words, a transistor detector. Do you know anything about this technology — if indeed it exists? If so, can you direct me to a source where I can find out more about it?

Mike Johnson
via Internet


Oh yes, it exists. This isn't a James Bond pipe dream from Hollywood. How does it work? Using magic and a divining stick. Kidding, it's a natural property of a dissimilar junction. When a semiconductor junction is drenched in a low-power microwave signal, it resonates much like a quartz crystal and generates overtones — harmonics. It's the second harmonic that defines a transistor from rusty metal, also a dissimilar junction, which has its strongest peak at the third harmonic. A sensitive receiver can detect and sort these harmonics to identify "bugs" even if they're not powered up. For more information go to