FIELD: electronics.
SUBSTANCE: invention relates to the detection of metal objects hidden in various environments, in particular in weakly and highly mineralized soil, walls of buildings, etc. Essence: a universal selective induction metal detector contains a measuring generator with an oscillatory circuit in a positive feedback circuit formed by an inductor and a capacitance box, a computational microcontroller and an indication unit. The measuring generator is made on parallel CMOS logic elements of microcircuits and additionally contains a linear voltage stabilizer to ensure the stability of the supply voltage of the measuring generator, precision and protective matching resistors, a connector for connecting via cable to a digital pulse duration converter unit, the output of which is connected to a computational microcontroller. At the same time, the logic elements connected in parallel to the CMOS through the linear voltage stabilizer and through an additional logic element that performs the functions of a buffer and current amplifier of the output signal line of the generator, and a protective matching resistor are connected to the connector terminals. The precision resistor is connected in series to a positive feedback circuit to match the total resistance of the oscillating circuit network with the total dynamic range of the load capacity of the output current of the parallel connected logic elements. The capacitance box is made in the form of parallel ceramic capacitors with a capacity of <2.2 nF connected to the terminals of the inductor. Moreover, the capacitances installed in each arm of the inductor are equal.
EFFECT: recognition of a wide class of metal and metal-containing objects, magnetometric discrimination by ferrous and non-ferrous metals, high sensitivity with low power consumption and a wide range of batteries used, stable sensitivity with fluctuations in the supply voltage in the range of 6.5-30 V to small and large objects of all types of metals and alloys.
4 cl, 3 dwg
