Skin conductivity measuring circuit - comprises wheatstone bridge with low voltage DC supply, digital meter and can be incorporated in bracelet

摘要

The skin conductivity monitoring device includes two contacts (10,12) placed on the skin, connected into a Wheatstone bridge circuit with three other resistors (R1-R3). A small direct voltage is applied to one contact (12) and the opposite corner of the bridge at the junction of two resistors (R1 & R2). A digital display meter (16) is connected across the other two corners of the bridge circuit - the junction of two resistors (R2,R3) and the junction between one contact (10) and the first resistor (R1). A threshold circuit (18) is connected across the meter display, to provide a warning signal (20) when certain preset limits are exceeded. The circuit may be incorporated into a band worn around the subject's wrist. The device can be used in industrial psychology, psychiatry and police interrogations of suspects and witnesses.