Determination of electrical capacitance and resistance

Abstract From the Canadian patent

Apparatus and method for determining capacitive and resistive values of an electrical component such as a fuel, level determining probe includes a waveform generator for, subjecting the probe to a time-varying waveform that includes a linearly varying ramp portion and a fixed constant, portion. A selectively controlled sample and hold circuit senses the voltage potential of the probe in response to a zero crossing detector during the linearly varying ramp portion of the waveform to provide information indicative of the capacitive value and again senses the voltage potential at selected time thereafter during the fixed portion of the waveform to provide resistive value information. The …