Abstract: A charge-controlled integrating successive-approximation analog-to-digital converter first stores a charge proportional to an unknown voltage in a manner similar to a dual-slope integrating ADC, and thereafter a successive-approximation binary search sequence algorithm is applied to the integrator to determine digital bits representative of the unknown voltage. The result is a relatively simple and inexpensive ADC having high resolution and accuracy, and comparatively fast conversion rates, and exhibiting low power consumption, high noise rejection, and multiple-speed versatility. The preferred embodiment described is a 16-bit ADC with less than 20 millisecond conversion time.

Abstract: An oil level sensor includes a sensor body adapted to be mounted to the block or casing of an oil-containing reservoir. A probe including a pair of electrodes forming a capacitor extends from the sensor body so that the capacitor will be at least partially immersed in the oil to detect the level thereof. At least one of the electrodes is insulated so that the apparent capacitance of the capacitor is relatively insensitive to any change in the conductivity of the oil at high temperatures. Circuitry is provided in response to the capacitance of the capacitor for signalling the level of the oil, which capacitance is a function of the oil level. The sensor body is mounted to the block by external threads on the probe. The electrodes of the probe extend proximally past the threads to provide an increased capacitance for the sensor. The electrodes of the probe are concentric and the inner electrode is supported at both ends to reduce fatigue.

Abstract: A detector system for sensing the presence, or absence, of electrically-conductive liquid in contact with two probe members. The system includes switchable voltage sources to selectively establish a potential across capacitors connected to the probe members, and detection systems for sensing the magnitudes of charges on the capacitors. The magnitudes of the sampled charge at given intervals is indicative of the presence, or absence, of ionic liquid in contact with the probe members.

Abstract: There is provided according to the invention a method and apparatus for eliminating or minimizing the error due to amplifier offset or drift error in an integrating dual slope analog-to-digital converter. The converter is provided with a switching and control arrangement whereby the integrating capacitor is charged for one-half of the predetermined charging time as a function of the sum of the levels of the unknown signal and the error signal. The integrating capacitor is charged for the remaining half of the predetermined time period as a function of the difference of the levels of the unknown signal and the error signal so that the capacitor reaches a level of charge which is a function of the level of the unknown signal substantially unaffected by the level of the error signal.