How Do Metal Detectors Work?
Metal detectors work by transmitting an electromagnetic field from the search coil into the ground. Any metal objects (targets) within the electromagnetic field will become energized and retransmit an electromagnetic field of their own. The detector’s search coil receives the retransmitted field and alerts the user by producing a target response.
- Battery The battery provides power to the detector.
- Control Box The control box contains the detector’s electronics. This is where the transmit signal is generated and the receive signal is processed and converted into a target response.
- Search Coil The detector’s search coil transmits the electromagnetic field into the ground and receives the return electromagnetic field from a target.
- Transmit Electromagnetic Field The transmit electromagnetic field energises targets to enable them to be detected.
- Target A target is any metal object that can be detected by a metal detector. In this example, the detected target is treasure, which is a good (accepted) target.
- Unwanted Target Unwanted targets are generally ferrous (attracted to a magnet,) such as nails, but can also be non-ferrous, such as bottle tops. If the metal detector is set to reject unwanted targets then a target response will not be produced for those targets.
- Receive Electromagnetic Field The receive electromagnetic field is generated from energised targets and is received by the search coil.
- Target Response When a good (accepted) target is detected the metal detector will produce an audible response, such as a beep or change in tone. Many Minelab detectors also provide a visual display of target information .