DEVICE FOR MEASURING FRIABILITY OF EPITHELIAL TISSUE OF ALIMENTARY CANAL Russian patent published in 1995 - IPC

FIELD: medical equipment. SUBSTANCE: meter has variable frequency voltage source, two electrodes, operational amplifier, two detectors, voltage relation converter and measuring unit. To prevent patient against electric current affection, the meter is provided with protection unit which has two blocking capacitors, commutator, control unit and correction circuit. Blocking capacitors permit to provide constant current galvanic de-coupling between tissue to be tested and working part of the meter. Commutator and control unit permit to perform alarm interruption of entering of variable measuring current into biological tissue if the current excesses over the threshold value. Correction circuit has analog adder, digital-to-analog converter, correction code register, phase-shifting unit, balance resistor. Correction circuit permits to compensate errors when measuring some values in members of protection unit. It also permits to improve precision of measurement of electric resistance of epithelia tissue at different frequency of measuring current. Absolute value of total electric resistance of epithelia tissue may be measured within the range of 10 to 100 Ohms with absolute error ± 3 at two frequencies of measuring current (moved apart no less than for one order). EFFECT: improved precision of measurement. 8 dwg