DEVICE FOR MEASURING CONDUCTIVITY Russian patent published in 2007 - IPC G01N27/02 

FIELD: measuring technique.

SUBSTANCE: device comprises contact pickup of conductivity provided with two current and two potential electrodes, direct voltage power source, square pulse generator, four-arm bridge commutator provided with controlled switches in the arms whose control input are interconnected in pairs and connected with the output of the generator of square pulses for first pair directly and for the second pair through the inverter, demodulator controlled by the generator of square pulses, and low-pass filter. The second top of the first diagonal of the bridge is grounded. The device is additionally provided with the source of reference voltage whose outlet is connected with the first input of the first operation amplifier whose output is connected with the base of the transistor whose emitter is connected with the first top of the first diagonal of the bridge commutator the tops of the second diagonal of which are connected with the current electrodes of the pickup. The potential electrodes of the pickup are connected with, connected in series, demodulator, low-pass filter, and instrument amplifier whose output is connected with the second input of the operation amplifier. The collector of the transistor is connected with the output of the source of direct voltage. The outputs of the loading resistor are connected with the inputs of the second operation amplifier whose outputs a the output of the device.

EFFECT: enhanced reliability.

1 dwg