Abstract: The present disclosure provides a method and an apparatus for measuring electrical conductivity of liquids. In one aspect, the apparatus includes a waveform generator module configured to generate a first waveform signal and to supply the first waveform signal to a sensor; a phase adjustment module configured to receive the first waveform signal from the waveform generator module and to generate a phase-shifted signal from the first waveform signal, said phase-shifted signal having a phase that is adjusted based upon expected or measured properties of the liquid and further adjusted to eliminate phase error induced inaccuracies in the measurement; and a signal combination module configured to receive a return signal from the sensor and the phase-shifted signal from the phase adjustment module and to sum the return signal and the phase-shifted signal to produce an adjusted return signal containing information associated with the electrical property of the liquid.

Abstract: The present disclosure provides a method and an apparatus for measuring electrical conductivity of liquids. In one aspect, the apparatus includes a waveform generator module configured to generate a first waveform signal and to supply the first waveform signal to a sensor; a phase adjustment module configured to receive the first waveform signal from the waveform generator module and to generate a phase-shifted signal from the first waveform signal, said phase-shifted signal having a phase that is adjusted based upon expected or measured properties of the liquid and further adjusted to eliminate phase error induced inaccuracies in the measurement; and a signal combination module configured to receive a return signal from the sensor and the phase-shifted signal from the phase adjustment module and to sum the return signal and the phase-shifted signal to produce an adjusted return signal containing information associated with the electrical property of the liquid.

Abstract: A meter pulse initiator is employed to generate signals corresponding to the rotation of the rotor of a watthour meter. Infrared light emitting diodes (IREDs) receive a small steady state driving current and radiate two low intensity beams of radiation that are reflected from the surface of a rotating rotor. A creep hole in the rotor passes beneath one of the beams and transmits the low intensity radiation to an associated phototransistor. A small current is induced in the phototransistor and the current is amplified by a Darlington amplifier. The amplified current is applied to the IRED to increase the intensity of the radiation of the IRED in a positive feedback loop. Component saturation defines a peak driving current and an associated peak radiation intensity for the IRED. As the phototransistor current increases, a capacitor is charged to a threshold voltage and after the creep hole passes the IRED/phototransistor pair, the capacitor discharges.