Analog-to-digital tester

摘要

An analog-to-digital tester having at least two distinct ranges of full scale sensitivity is provided. The tester includes signal conditioning means for receiving an analog measurand and digital display for displaying a value representative of the measurand. The signal conditioning means includes first and second attenuation levels differing by a multiple of at least 100 and circuit means for selecting the attenuation level corresponding to the magnitude of the measurand. The analog-to-digital converter circuit has full scale sensitivity over a first range and additionally full scale sensitivity over a second range ten times greater than the first range and includes range detecting means for detecting the magnitude of the measurand applied to the signal conditioning means and in response thereto selects the first or second full scale sensitivity range to thereby apply a digital value representative of the measurand to the digital display. Combinations of selected sensitivity and attenuation levels provide at least four ranges of measurand values for display. Measurands include AC voltage, DC voltage and resistance.