Batteryless ohmmeter
First Claim
1. A batteryless ohmmeter including a meter provided with a plurality of calibrated scales comprisinga. a battery test circuit including a chargeable energy storage device,b. a constant current generator in circuit with said energy storage device and through which current is discharged into the meter,c. a pair of test leads provided by said battery test circuit and adapted to be momentarily connected to an external voltage source for charging said energy storage device, andd. a resistance-measuring network including the meter in circuit with said constant current generator for determining the scale calibration of the meter when said battery test circuit is in use.
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Accused Products
Abstract
An ohmmeter and circuit therefor which does not require an internal battery or a continuing coupling to an external voltage source during normal use, with the necessary operating electrical power supplied through a high capacity capacitor which, after initial energization by a temporary connection to an external voltage source, develops a stored source of operating power. As the operating current is constant, there is no necessity for scale adjustment prior to each use of the ohmmeter.
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Citations
6 Claims
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1. A batteryless ohmmeter including a meter provided with a plurality of calibrated scales comprising
a. a battery test circuit including a chargeable energy storage device, b. a constant current generator in circuit with said energy storage device and through which current is discharged into the meter, c. a pair of test leads provided by said battery test circuit and adapted to be momentarily connected to an external voltage source for charging said energy storage device, and d. a resistance-measuring network including the meter in circuit with said constant current generator for determining the scale calibration of the meter when said battery test circuit is in use.
Specification