Now, by changing the inductance of
the inductor, you will drastically change the amplitude of the output voltage.
It just so happens that by simply bringing a metal into the vicinity of the magnetic field of
the inductor, will change the inductor’s inductance –
after all an inductor works by using
magnetic fields to store current! In this case I place a US quarter on folded paper so that there is space between the inductor and the coin.
Making a functional working metal detector using a simple voltage divider circuit. You do not need much electrical experience to follow this article.
And the result: The voltage drastically changes -
And that is a metal detector. Simple as that!