El escenario
A hobbyist needs a readable BFO metal detector schematic that clearly separates power, oscillator, mixer, comparator, and indicator stages.
Qué hay en este dibujo
Lee las decisiones que hay detrás.
01
Use two BF422 Colpitts-style oscillators (search and reference) to produce a beat note.
02
Use a 7805 regulator to derive a stable 5 V rail from a 12 V battery.
03
Use an LM339 comparator to square up the detected envelope.
Reuse when building or documenting a classic BFO metal detector and you need a clean, auto-routed netlist rather than a positional wiring diagram.