Bifilar oscillator metal detector

Published:2012/9/13 21:05:00 Author:Ecco | Keyword: Bifilar oscillator, metal detector | From:SeekIC

Its performance is not comparable to more advanced commercial products, of course, but it still works. Anyway, during WWII metal detectors based on the same principle were utilized my combat engineers of many armies to clear mines. The main idea is really quite simple: build two identical oscillators and adjust them to the same frequency. One of the oscillators uses the search coil while the second one incorporates a variable inductor. When both are operating at the same frequency, the output is zero. If the search coil moves near any metal, however, frequency of the first oscillator shifts and an audible tone is heard in the headphones. Source: NEXT.GR



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