Infrared thermometer

Temperature can be measured by several methods. Each of them has advantages and disadvantages. For example, mercury thermometer which uses fluid to convert heat in to expansion, thus we can see rise of height when temperature increase. This thermometer is very simple.

Thermocouple is inexpensive sensor temperature. This sensor consists of two different materials and both of them are connected by junction at one of their edge of. When temperature of junction is getting higher this junction produces more voltage which can be converted to temperature value. The disadvantage of this sensor is we need interface that convert from voltage to temperature.

The other thermometer is infra red thermometer. Every molecules move if their temperature is above absolute zero. Higher temperature causes faster movement of molecules. When the molecules move, they emit infrared radiation. If they move faster, more infrared radiation emitted. Sometimes if the temperature so high, they emit visible light. For example, metal will glow red when it is heated until very high temperature.

This phenomenon is called black body radiation and this is the principle of infrared thermometer. Infrared radiation can be focused, absorbed or reflected. Infrared thermometer has lens to focus this radiation and it will be received by detector/sensor. This sensor is called thermopile. Thermopile absorbs infrared radiation and converts it into electricity, then this electricity is converted to show the temperature of the object.

Infrared thermometer is usually completed with laser or LED that can emit beam from that thermometer. It is just for show what you are measuring at. The advantage of this thermometer is noncontact measurement, so this thermometer will not affect the system want to be measured. Furthermore, it can be used from the distance.