Metal detectors are devices used to locate metal or metallic objects below the surface of the ground. They can be helpful in various situations, from prospecting for buried treasure to find weapons caches.
There are two types of metal detectors, and they are referred to as coil detectors and electromagnetic or induction detectors. The coil detector used in buried treasure hunting contains galvanic cells and a carbon microphone. The electromagnetic or induction detector has an electromagnet called a solenoid, and it uses eddy currents from nearby metal objects to auxiliary power coils. Both types of millimeter band sweepers use a similar principle.
Metal detectors typically have one or more search modes. These can be selected by turning a knob or pressing a button. The most common “mode” the user will use is a metal mode that selects ferrous materials like iron, silver, and bronze. The next mode (sometimes called “audio”) is for non-ferrous materials like gold, copper and aluminum. Some units incorporate a multi-metal mode that detects all metals in the field simultaneously. Experienced treasure hunters often use a sensitivity control, which varies the power level of the detector’s internal electronics and uses notches to reject unwanted metallic responses. The notch can be used to eliminate undesirable reactions from certain classes of objects, like coins or “hot rocks” that give false signals due to their mineral content. Advanced metal detectors will have buttons or knobs for such functions as frequency selection and ground balance.
Working of a Metal detector:
The basic principle behind the operation of a metal detector is that metals contain eddy currents. When a metal moves through a magnetic field, it induces magnetic fields in the metal. The circuit carries the “eddy currents” which circulate through the metal. The eddy currents and hence, the response from any piece of buried metal will decay rapidly with time and distance from its source. This means that to detect deeper objects to use a more sensitive system. Some metal detectors have a color display that displays the strength of the signal at a particular depth.
The process of detecting using a metal detector:
The detector user moves the probe slowly over the ground, then brings it up to the surface again and moves gradually along until he hears a tone indicating that the probe has touched some object that is not metal, such as glass, stone or wood. If the detector comes across one or more objects that are not metal, he will have to decide what object is causing the signal.
There are many different styles of metal detectors. One of the most common types is an antique detector, a low-frequency coil detector that searches for ferrous metals buried in the ground previously disturbed by humans and animals. The military uses these for detecting unusual findings in war zones before sending in soldiers to investigate.
Common uses of a metal detector:
Metal detectors are used in many cases. They are used to locate stumps, metal objects, and even metallic artifacts like old coins, pieces of jewelry, etc.
Metal detectors are handy for prospecting with a metal detector. They help people find various types of metals that they can use to make different products, such as jewelry or precious metal coins. Many people find different kinds of metals by using a simple metal detector carried by them.
Metal detectors are also used in criminal investigations. Police officers use metal detectors during criminal investigations and crime scene searches to find all the proof needed to convict a person.
Metal detectors are pretty helpful for a variety of purposes. They can be used for prospecting for buried treasure and detecting weapons as well. Moreover, a metal detector searches out buried metal based on the principle of electromagnetic induction. The best part about these devices is that they are easy to use and can be used in different situations by anyone.