FIELD: physics.
SUBSTANCE: capacitive sensor includes an oscillatory circuit which excites current pulses with different direction and frequency scan velocity in two transformation cycles. Deviation of the amplitude of the oscillatory circuit signal from the threshold voltage is detected and amplified and then used to control amplitude of current pulses. The resonance frequency is determined from zero phase difference between the exciting current and the oscillatory circuit output signal. Moisture of the material is determined from the result of digital measurement of the resonance frequency.
EFFECT: high accuracy of measuring moisture.
1 dwg
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SU1614003A2 |
