Electromagnetic theory of operation of the device to detect underground metal
Consists of metal detectors parts of the electromagnetic system is simple and light weight are as follows:
(1) is installed and used in parts of the device to maintain constant and stable as you move the device forward and backward.
(2) control box contains the electronic circuits and control devices, battery, and Almikrobrossor and speakers
And indicators Amp Monitors (LCD) that is found in the device.
(3) the column that connects the control box for a metal detector and the column is usually subject to control in length to suit
The length of the person who uses without tiring
(4) Detector, a main part in the device used in detecting the presence of minerals and is sometimes called the head
Gravel or Alantena or file. "We will use the term detector."
Parts of a metal detector
Different metal detectors from each other sometimes slight variations such as to be each equipped with a headset additional or different in the place of the remote control and screen control, but all these devices operate on the principle of one and the same effectiveness of one and different power circuit to detect only, all of which are easy to use everything that the user to do is run the device and move the detector slowly over the area to be where the metal detector. When there are no targets, metal, the device will be voice over headphones as it appears on the screen some information about this type of metal.
Types of metal detectors
Based metal detectors to identify three kinds of techniques and these techniques are:
• Technology low frequencies (Very low frequency (VLF
• Magnetic pulse induction technology (Pulse induction pi
• Tguenipalndat fluctuation (Beat-frequency oscillation (BFO
. We can explain these techniques and how they work on metal detectors each technique, including:
First: the low-frequency technology
This technique is most commonly used in metal detectors, and sometimes known as induction balance Almanatisi induction balance and rely on the use of this technique are the two files:
- File transmitter, a transmitter coil and the external file that contains a loop of wire in which electric current passes once in a clockwise direction and once in the clockwise rotation to a rate of up to thousands of times per second.
- File reception receiver coil which is the internal file that contains a wire in the form of a radius smaller than the file transmission and works of this file work Alantena to receive the signal reflected from objects in the earth and enlarge it.
The alternating electrical current passing through the file transmitter establishes a magnetic field, the direction of the magnetic field perpendicular to the file level transmitter, and each time it changes the current direction of change polarity (North Pole and South Pole) magnetic field. This means that if the file level transmitter completely parallel to the surface of the earth's magnetic field arising in the land, enters or goes out of them in a process similar to payment and clouds. While the pulses of the magnetic field within the Earth and out of interacting with any conductive material (eg metal) collide with them, and this causes that generate material connected to a magnetic field is weak so-called magnetic fields of the body and have the polarity of the field opposite polarity magnetic field of the file transmission. If the file is in the direction of entry to the earth shall be the area of the body in the direction of exit and vice versa.
We come now to the role of a receiver to show how magnetic receives the signal reflected from the metal body, a reception here is completely isolated from any magnetic field issued by the file transmission, but not isolated from the magnetic field of the metal body is located in the ground. That is when one passes over a metallic object receiver issued a magnetic field because of the file transmission, the file receiver will pick up this magnetic field is weak and the AC and produces electric current that passed, in a receiver, frequented the same frequency electrical field Amonatabisi. This is maximized and the intervention of the electrical box to control where the Almikrobrossor analysis of the signal and show the data.
We come now to the role of a receiver to show how magnetic receives the signal reflected from the metal body, a reception here is completely isolated from any magnetic field issued by the file transmission, but not isolated from the magnetic field of the metal in the body in the ground. That is when one passes over a metallic object receiver issued a magnetic field because of the file transmission, the file receiver will pick up this magnetic field is weak and the AC and produces electric current that passes in a receiver, frequented the same frequency electrical field Amonatabisi. This is maximized and the electrical interference to the Fund where the Altjkm Almikrobrossor analyzed the signal and show the data.
The metal detector determine the depth of the metal body in the ground depending on the intensity of the magnetic field generated by the metal body, the higher the body near the surface of the earth where the magnetic field emerging bigger and greater the electrical signal generated in a receiver's largest and whenever the body at a depth greater than the surface whenever the earth's magnetic field was smaller and through the calibration of magnetic field strength with depth can be the device that identifies the location of the body and its distance from the earth's surface.
How a metal detector distinguishes between different types of metals?
You may not imagine how many minerals that can be picked up a metal detector and you end up either a small nail or plug a drink from Almcorbac or scrap metal have been developed metal detectors to let you distinguish between metals shall be determined in advance for your kind of metal that you want to search for such as gold or other and therefore does not give the device the audio signal only if the Find metal you are looking for, but how can a metal detector to distinguish between types of metals has our understanding of how to set a limit to the depth and the process was easy and clear, but to distinguish between metals, it really is difficult and depends on the circuits E is the measurement of displacement in the phase phase shifting.
Displacement in the phase is the difference in time between a transmitter frequency and the frequency of the body. This difference in time due to the different metals to resist electrical resistance in the electric induction inductance.
This means that the body which has Inductance have a large amount of displacement in a large phase takes time because the biggest change in the magnetic field either with objects that have a large electrical resistance, the amount of displacement in the phase will be small.
Depending on the electronic circuits Bsbitp can calculate the offset in phase and compare the displacement of the information stored in advance of the displacement in the phase of the various metals can be for the device to distinguish between metals and therefore can be programmed a metal detector to look for metals that have a displacement of the process certain is that we want.
Second: the IT pulse magnetic inductive
Technology is considered a pulse magnetic induction less commonly used in metal detectors because based on this technique can not be distinguished between the types of metals as in the technical, but the first devices that support the technology works in certain areas where they can not use the technology first as we will see after a clear idea of reagents based inductive magnetic pulse technology.
This technique uses a single file works as send and receive at the same time. The idea of this technique to send an electric current in the form of short pulses and in a strong component of a wire in the form of a pie. Each pulse of the pulses generate a magnetic field. When the end pulse reflected polar magnetic field and magnetic field suddenly fading problem in this way an electric spark. The duration of the electrical spark does not exceed Almaekerothanip (ppm of a second) causing the electrical spark passing electric current in the file. This is called the electrical output of the electric spark on behalf of the reflected pulse and the reflected pulse to be a very short period of time not exceeding 30 microseconds. This process is repeated a rate of 100 beats per second and can change this number to up to 25 beats per second or more to 1000 beats per second according to the manufacturer.
How can a metal detector metal detector with this technology?
When the metal detector over the body of the electrical pulse produces a magnetic field in the body. When the fading pulse and caused the reflected pulse reflected pulse, the magnetic field caused by the additional metal body will work to increase the survival time of reflected pulse. This process is quite similar to the phenomenon of echo the more reflectors (walls), the echo lasts longer.
Using an electronic circuit monitors the time period of the pulse can be reflected to the Department determine if there is an additional magnetic field due to the increased survival time of reflected pulse. If the time was more than the expected value, the device sends an electric signal transferred across the circuit to grow up and sent to the Department issue a voice warning of the existence of a metallic object in the area that disclosed in the earth.
Advantages and disadvantages of inductive magnetic pulse technology
Reagents that enabled pulse magnetic induction as we mentioned at the outset can not distinguished between types of metals because the time period of the reflected pulse is not much different between the metals. But is this technique very useful in cases that can not use reagents that enabled low frequencies due to the nature of the land that scrutiny if the earth was containing materials conductivity of highly preferred to use the detectors pulse magnetic induction, and that these reagents can detect metals at distances deeper than those that learn to other systems monitoring.
Third: Technology fluctuation pulses
Technology is considered a pulse fluctuation of the easiest techniques used in metal detectors. Used where a large file on the edge of research and another smaller one located inside the control box. Each file is connected Bmzbzb generates thousands of pulses per second.
Shall file radio waves received by a receiver in the control box and turn it into audio signal heard in the form of pulses produced by the difference in frequency Balmelvin.
When a large file over a metallic object, the magnetic field is generated as a result of electrical current that flows in the file. Interfere with the magnetic field of the metal body with radio waves, and this leads to deviation in the frequency of radio waves and radio waves for various of the file is located in the control box, which generates pulses that have a distinct tone audible.
The simplicity of the idea of technology pulse fluctuation, many of the producers adopted this technology for metal detectors for low cost and the possibility of purchase by anyone and used as a household. But it must be pointed out that the accuracy and sensitivity of these devices is less than those that rely the above-mentioned techniques
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