Metal detector

摘要

The invention relates to a metal detector with a differential transformer which has a transmission coil arrangement and a receiver coil. In this case, the transmitter coil arrangement consists of two mutually concentric ring coils which are connected to the AC voltage source in such a way that in operation they carry currents which flow with the same sense and are tuned with respect to one another in such a way that the voltage induced in the receiver coil vanishes at least approximately when the field is undisturbed.