Metal detector's debugging and operation method
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Metal detector circuit in addition to sensitivity adjustment potentiometer, there is no adjustment part, as long as the welding is correct, the circuit will be able to work properly. The total current is about 10mA when the whole machine is static, that is, when the speaker is not sounding. When the sound of the metal speaker is detected, the whole current rises to 20mA. A new battery pack can work for 20 to 30 hours.
If the newly-welded metal detector fails to work properly, first check whether the components on the circuit board and the wiring are soldered incorrectly. Then measure the battery voltage and the power supply circuit. Check whether the voltage regulator diode VD1 is between 5.5 and 6.5V. VD2 polarity should not be reversed. Detect the inner and outer ends of the oscillation coils in the dish.
Before the metal detector is used, the length of the detecting rod needs to be adjusted, as long as the vinyl is loosened, the rubber is pushed through the sleeve to an appropriate length, and then the plastic inner tube is rotated to tightly wind the cable and the handle is pointed upward. Finally, tighten the black rubber and lock the plastic through the sleeve. In this way, when holding the probe handle, the thumb just close to the sensitivity adjustment potentiometer.
Adjust the sensitivity of the metal detector, the detection disc (oscillating coil) to stay away from metal, including paper with aluminum foil, and then turn the sensitivity fine-tuning potentiometer knob (FINETUNING) to turn on the power switch, and rotate to half position, and then adjust the coarse adjustment potential The knob (TUNING) stops the speaker's audio calls, and then fine-tunes the fine-tuning potentiometer so that the sound of the speaker stops just. At this time, the metal detector has the highest sensitivity. When detecting a metal with a metal detector, the sound is emitted by the speaker as long as the detection of the dish is close to any metal, and the sound is automatically stopped away from a certain position.
The metal detector has a high sensitivity. When it is used to detect large pieces of metal, the detection of the disc from the metal object 20cm speaker will emit sound, as small as paper clips, and even a pin can be detected, but the detection coil must close Small metal objects. Since the metal detector uses the electromagnetic induction of the oscillating coil to detect metal objects, it can detect the covered metal objects through non-metallic objects such as paper, wood, plastics, masonry, soil, and even water layers. For example, when decorating a house, it is used to detect wires or steel bars inside walls to prevent construction risks and safety hazards; for example, metal detectors used in security inspections are based on this principle.