Smoke detector Reference Libraries
A metal detector is a device that finds metal that may not be visible. The basic metal detector is composed of an oscillator producing an alternating current that passes through the coil producing an alternating magnetic field. If electrically conductive metal is close to the coil then the magnetic field is disrupted and thus the metal detector can sense the hidden metal. The first metal...
- A handkerchief.
- In general, any miraculous portrait of Christ.