Patent ID: 9739740
Date: 2017-08-22
CPC Classifications: G01N

Claim:
1. A fluid sensor comprising: an oscillator having operating characteristics, wherein the frequency of the oscillator is greater than 1 MHz, the oscillator comprising driving electronics and a resonant circuit coupled to the driving electronics, the resonant circuit comprising: an inductor and a capacitive permittivity sensing element arranged to alter the operating characteristics of the oscillator in response to changes in permittivity presented to the permittivity sensing element; a first output that varies with a first operating characteristic of the oscillator as a real component of the permittivity presented to the permittivity sensing element changes; a second output that varies with a second operating characteristic of the oscillator as an imaginary component of the permittivity presented to the permittivity sensing element changes; a first reference element comprising a capacitor of known capacitance and a resistor of known resistance controllably coupled to both the inductor and the permittivity sensing element and arranged to alter the operating characteristics of the oscillator when so coupled; and a second reference element comprising a resistor of known resistance controllably coupled to both the inductor and the permittivity sensing element and arranged to alter the operating characteristics of the oscillator when so coupled.