ALARM DEVICE Russian patent published in 1994 - IPC

FIELD: automatics. SUBSTANCE: device has rectangular pulse generator 2 including operational amplifier 3, capacitive sensitive member 1, resistors 4,5, voltage divider 6, stabilizer diodes 7,8; converter 9 for converting a sensor signal into unipolar voltage, converter 9 being composed of operational amplifier 14, diodes 12,18,19, capacitors 10,11,20, resistors 13, 15,16,17,21. The device furthermore has reference signal source 22 including variable resistor 23, differential amplifier 24 made on the base of for instance, operational amplifier 28, resistors 25, 26,27,29; comparator 30 including resistors 31,32 and operational amplifier 33, and unit 34 for generating an alarm signal. EFFECT: enhanced sensitivity, reliability and simplified construction. 1 dwg