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  1. #1
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    Information Regarding working of BFO metal detectors in proteus

    AOA. I had made BFO metal detector circuit on proteus but the IF transformer is causing problem. and also the buzzer at the end is not showing anything. and if I check the output at oscilloscope it aslo shows nothing. Plese help me out.

    •   Alt20th October 2016, 13:21

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  2. #2
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    Re: Information Regarding working of BFO metal detectors in proteus

    As I understand it, the principle is to get two coils oscillating at the same (or nearly the same) high frequency. The coils are air-core. A metal core would interfere with the ability to detect metal.

    Bring metal close to one coil, which should alter its oscillating frequency. This creates a beat (difference) frequency between the oscillators. The beat tone is in the audible range, as long as your oscillating frequency is high enough, and the coils are sensitive to metal in proximity.

    Listen via headphones for the beat tone. Do not use everyday 8/ 16/ 32 ohm headphones, but high impedance (example, crystal) phones. The problem is to figure out where to take output, so that you get the strongest beat tone, yet you must avoid interfering with the coils oscillating.



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