DEVICE FOR INDICATION OF SKIN ELECTRICAL ACTIVITY Russian patent published in 1997 - IPC

FIELD: medical engineering; estimation of man functional state. SUBSTANCE: the device uses an element of dielectric material, three electrodes connected to a bridge ensuring circuit comprising two resistors cut in the Whetstone bridge arms, unbalance meter and a power source connected across the measuring diagonally opposed pair of junctions and across the power diagonally opposed pair of junctions respectively. The calibrating circuit uses three resistors, one lead of each resistor is connected to the third electrode; two of these resistors are connected to the vertices of the power diagonally opposed pair of junctions via twinned switches. The third resistor is connected in parallel with the second one via a normally-open button. The unbalance meter is a DC differential amplifier, and the first and second electrodes are connected to the vertices of the power diagonally opposed pair of junctions and shunted by a circuit consisting of series-connected first resistor, variable resistor and second resistor. The midpoint of the variable resistor serves as one of the vertices of the measuring diagonally opposed pair of junctions and is connected to the inverting input of the DC differential amplifier; connected to the other vertex of which are the third electrode and the non-inverting input of the differential amplifier; the electrodes are fixed to the dielectric element in such a way that the first and second electrodes are installed symmetrically relative to the third electrode. The dielectric element is made in the form of a plate, and the electrodes are installed in line on its one side. The dielectric element may be made in the form of a cylinder, and the electrodes are made in the form of rings placed coaxially on its element. Besides, the dielectric element may be made in the form of a spring- loaded clip, the electrodes are placed on its inner surface so that the first and second ones are positioned on the same surface, and the third electrode - on the opposite part of the surface. EFFECT: enhanced effectiveness. 4 cl, 5 dwg