Current measurement with the application of a non-contact thermometer

A non-contact ac and dc current measurement method in the range of milliamp is recently required in the precise engineering field. Although some current measurement families introduced highly advanced current measurement system, interfaces such as interferometers and oscilloscopes are still required for the current measurement and calculations. In this paper, we propose a method of the internal current measurement of a model resistor by measuring its temperature when the current passes through the resistor. We use a non-contact thermometer for the temperature measurement. We clarify the relations of the temperature rise, power consumption and current. The current is in proportion to the power consumption of the target object. The current is estimated by measuring the temperature rise of the object.