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| METAL DETECTORS |
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| Just like most early inventions, metal detectors were initially crude instruments which were, of course, not anywhere as advanced as today’s models. However, both older and modern-day versions of metal detectors use the same operating principles - that is to say that they use electromagnetic signals to detect metal objects or traces of metal inside solid objects. Having stated this, it should be mentioned that there are exceptions to this rule. This is because some manufacturers have come up with a new kind of metal detector. Unlike other detectors, these fire a high voltage of electricity into the ground in order to detect even the slightest traces of metal. This process is known as pulse induction. The detector also has an electronic box that measures the amount of voltage received from any detected object. If metal is present in the ground, then the user would know this by the longer time it takes for the voltage meter to fall to zero. On the other hand, if there is no metal, the voltage meter would show a flat-lined frequency signal.
The original detectors typically consisted of an electronic box, battery, telescoping shaft, insulated wires, and the coil. The coil was comprised of a network of sensitive wires which were called “receivers”. Together with the battery, the coil was able to generate powerful electromagnetic signals which were used to detect specific magnetic signatures in the ground. In the case of metal being present, the receivers will read the charge and send the signals back to the electronic unit which contains the microprocessor. The microprocessor will in turn send the signal to a speaker which amplifies it into an audible beeping sound. It is worth mentioning that these metal detectors played significant roles in the finding of many important archeological artifacts.
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How Metal Detectors Work
Metal Detectors & Airport Security After 911
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| After these pioneering detectors there came an improved version, which was called the discriminator. This detector incorporated what is called the “induction balance system”. The system involved using a pair of coils that were set to read an equilibrium electrical frequency of zero. Once the coil comes across any metal in the ground, the frequency in the two coils will immediately become unbalanced. This in turn leads to a change in the sound of the detectors speaker. At the time when these detectors were manufactured, inventors had discovered that each metal has its own distinct response to electrical stimulation.
As such, manufacturers were now able to create a detector which could differentiate between metals. This feature is particularly important when one considers that some precious metals are in the same vicinity as lower value ones. In any case, the discriminator did have a flaw. This was due to the fact that making it less sensitive to metals like tin and copper and more sensitive to metals like gold implied that it was less likely to find deeply embedded objects. This is because setting the discriminator to find more precious metals meant that the coil lost much of its sensitivity.
Today the most sophisticated detectors are fully computerized and hence more efficient than previous versions. This means that they are also more practical in terms of size and portability. They use advanced microprocessors and microchip technology, which allows users to have access to an array of enhancing functions and features. At their fingertips, users can now set sensitivity levels, discrimination degrees, and track speed and threshold volume. It does appear that advancements in the production of detectors is set to continue well into the future. Whatever form the detector of the future takes, it is certain that they will be even more widely used. |
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METAL DETECTORS TYPES
