Then we were further amused by [Seraph’s] comment which added, “Resistance in the circuit: ‘Alright, I’ll take the energy, then.'” Of course, there are other ways to think of an LC circuit.

This LC meter circuit can measure coils and capacitors. When Lx or Cx is connected in the circuit the oscillator frequency will decrease and this decrease is measured by a frequency-voltage converter ...

The heart of this diy metal detector circuit is the CS209A IC. The metal detector is built with one 100µH coil that has 40 mm in diameter and is made of 50 turns/0.4 mm wire. CS209A has one oscillator ...