The initial metal detectors were created by Alexander Graham Bell in 1881 to spot the bullet wedged in President James Garfield’s body at the time of his assassinated and the first portable model was patented by Fischer in 1931. From that time it has become a very common gadget. Mentioned below are some facts about the workings of metal detectors.
What are metal detectors?
I t is an electronic device which can locate an occurrence of metal in the ground, parcel or a human body. It has been designed to see through sand, wood, soil or most other non-metallic objects and can track everything which is metallic.
How are metal detectors made?
A basic metal detector comprises of an electronic box which has a battery on one side and a handle to allow the operator to hold it. There is a coil made with insulated wire which is wrapped about the shaft used for telescoping and completes in a circular plastic disk. The disk moves out from the pipe and makes an angle which aids in maintaining parallel with the ground. The person using it holds the box and starts the power to begin moving the coil gradually on the floor or the surface till he can hear any electronic signal. This signal is a sign of the availability of some metallic substance under the region which is being swept by the metal detector.
How do metal detectors function?
Metal detectors work on electromagnetism principal and the kind of effect it has on all metals. There is a metal coil known as the transmitter which works on the power of battery and creates a magnetic field which works on the region. As this field gets into the surface or ground all metallic items become magnetic. This leads to the generation of an electronic signal which is perceived by the receiver present in the coil. After this the receiver sends the signal to the main electronic box. The sound becomes louder with the speaker and it generates a beep which can be heard by the person operating it. The basic electronic box comprises of microprocessors which calculates the time delay between checking the region and getting signal. This lag in time is known as the phase shift and allows you to identify which metals can be present. With the help of this principle, it is possible to constitute the more sophisticated metal detectors to locate particular metals.