METAL DETECTOR
BFO Metal Detector with LM339, 7805, BF422
A worked metal detector example, rendered live. Open it in the AI editor and adapt it to your own case.
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CASE ANALYSIS
Scenario
A hobbyist needs a readable BFO metal detector schematic that clearly separates power, oscillator, mixer, comparator, and indicator stages.
Key decisions
- Use two BF422 Colpitts-style oscillators (search and reference) to produce a beat note.
- Use a 7805 regulator to derive a stable 5 V rail from a 12 V battery.
- Use an LM339 comparator to square up the detected envelope.
When to reuse this
Reuse when building or documenting a classic BFO metal detector and you need a clean, auto-routed netlist rather than a positional wiring diagram.
RELATED EXAMPLES
More metal detector examples
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circuit-bfo-metal-detector-circuit-with-lm339-7805-bf422