The higher the optical resolution, i.e. increasing the D: S ratio, the higher the cost of the thermometer. The Raytek infrared thermometer D: S ranges from 2:1 (low distance coefficient) to over 300:1 (high distance coefficient). If the thermometer is far from the target and the target is small, a thermometer with a high distance coefficient should be selected. The capacitance and inductance tester has the characteristics of small measurement workload, fast and simple, stable performance, accurate measurement, and high fault detection rate. It can also be used for measuring electrical equipment such as CVTs and lightning arresters.

The non-contact infrared thermometer consists of an optical system, a photodetector, a signal amplifier, signal processing, display output, and other components. An optical system gathers the infrared energy emitted by a target object, focuses it on a photodetector, and converts it into corresponding electrical signals. After being processed by a circuit, it is converted into a linear temperature signal value of the measured target for further signal processing and control.