1. Metal Detector
2. X-ray
1. Metal Detector
Metal Detector
The simplest form of metal detector consists of an oscillator which produces alternating current that passes through a coil produces a magnetic field back and forth.
If a piece of electrically conductive metal near the coil, eddy currents will be induced in the metal, and this produces alternating magnetic field itself. If another coil is used to measure the magnetic field (acting as a magnetometer a), changes in the magnetic field due to metal objects can be detected.
Metal detectors
industry first developed in 1960 and is widely used for mining and other industrial applications. Uses include de-mining (mine detection), detection of weapons such as knives and guns, especially in the security of airports, geophysical prospecting, archeology and treasure hunting.
Metal detectors are also used to detect foreign objects in food, and in the construction industry to detect steel reinforcement in concrete and pipes and wires buried in walls and floors.
Basic Principles of Metal Detector
The basic principle of metal detectors is
1. A winding is given a certain voltage, will form the alternating magnetic field and cause induktance currents, magnetic fields is stable so that when the field magnitnya change will affect the value of his induktance
2. Serves as a oscillator generating a high frequency of certain
3. Mixer for mengabungkan between certain high frequency and comparing with
4. Low pass filter, if by definition is a circuit offers a low frequency signal part is easy and the hard part for high frequency signals.
5. Audio frequencies audio frequency amplifier strengthens
6. Speaker change the frequency of a sound wave
Metal detectors work on the basis of sensitivity and selectivity,
Sensitivity means it can detect the distance from the material with a mixture of metals, with the principle of a slight disturbance / Interferencense the magnetic field then it will immediately respond / alarm
Contrary to the selectivity we can mengaturkandungan metal which can disrupt / cause interference
