Importance

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Abstract

A device for indicating the state of charge of an electrochemical cell or battery includes a regulated-voltage generating circuit having an input connectable to the cell and an output providing a regulated reference voltage, an amplifying circuit having an input connectable to the cell and an output having a predetermined relation to a voltage within a predetermined range applied to the input of the amplifying unit, and a solid state analog display unit having a reference input connected to the output of the regulated-voltage generating circuit and an address input connected to the amplifying circuit. The relation between the address voltage output of the amplifying circuit and the cell voltage input is such that the address voltage corresponds to the state of charge of the cell in the predetermined range of cell voltages and falls within the range of the most negative and most positive values of the reference voltage. The device is adaptable for use as an integral state of charge indicator for a battery-operated tool or appliance or as a charge tester for different sizes and types of consumer batteries. One such battery tester has a housing shell provided with a plurality of shaped recesses, each recess receiving a single type or size of battery for test. A number of recesses are aligned so that a single spring-biased metal contact strip can be used for the number of recesses. The spring backing for the contact strip is a resilient pad of plastic foam material.

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First Claim