A world made of metal


Metal Detectors to Get That Rare Find

The first metal detector was invented byelectromagnetism affects on them.
Alexander Graham Bell in the year 1881,Magnetic field is generated in this
just after the invention of telephone indevice through the transmitter
1876. Later, Fischer came out with a(high-powered coil), getting power from
portable one in the year 1931. Today,the battery attached. When this
metal detectors are used in many fieldselectromagnetic field penetrates the
starting from treasure hunt to securityground the metals tend to get charged
purposes. These are electronic deviceswith magnetism. When this happens the
and are used to locate signs of metal.coil detects the electromagnetic
It is used to search on the ground,behaviour and sends a signal to the
people or goods. The materials can be onelectronic box. The speaker attached to
the ground may be a piece of iron,the electronic box beeps and the
aluminum, etc or it can even indicateoperator hears it and comes to know of
buried metal could be anything fromthe presence of metal. The latest
discarded pieces of aluminum to burieddetectors comprises of microprocessors
resources. These detectors can penetratein the electronic box that can give you
various non-metallic substances likethe type of metal present. It can
soil, wood, sand, etc.measure the time between charging of
Metal detectors have electronic boxesmetal and the receiving the beep that
with a battery case on one end and aconcludes the type of metal and this
handle for the operative's arm on thelength of time is known as phase shift.
other. It has a coil made of insulatedThere are adjustments in the device when
wire wound around a telescoping shaftsearching for a particular kind of
that is inside a plastic disk. Themetal.
device is held parallel to the groundThere are 3 types of metal detectors
due to the angle at which the disk comesfollowing 3 different technologies:
out of the shaft. The electronic box is1. Beat Frequency Oscillator: Such
held in the hand, the power is put ondetectors have a coil acting as an
and the coil end is slowly swept overinductor inside an oscillator. With
the ground. If the trace of metal isfrequency change there is a change in
there on or buried in the ground, aninductance. There is a second oscillator
electronic beep is heard when the devicethat generates a close frequency. The
sweeps the ground.beeps heard between them indicate the
The discovery of Electromagnetism was bypresence of metal.
Hans Christian Oersted in the year 1820.2. Induction Balance Detector: This type
It is the science of combined effect ofhas 2 coils that overlie each other. One
electric and magnetic field. As statedsends waves and the other receives. The
in wikipedia, Electromagnetism is thetwo are kept adjusted so that when there
science of the electromagnetic field.is absence of metal they do not indicate
That is, a field, surrounding all ofor beep.
space, which exerts a force on those3. Pulse Induction Detector: This type
particles that possess the property ofproduces pulses by putting off an
electric charge, and is in turn affectedindicator. A coil sends the pulse and
by the presence and motion of suchthe detector searches for echos.
particles.If you have a metal detector, I wish you
This principle of electromagnetism is onluck in finding all kinds of treasures.
which the Metal detectors work. SinceYou never know what "rare find" you'll
the metals are good conductor ofcome up with, and it's fun to look.
electricity and magnetism, the



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