The tip of the sensor has a spring that is attached to a rod, leading up to the gauge needle. The spring sits inside the stems sensing end. When heat is applied to the sensing coil, movement in the coil is created which causes the needle in the gauge to move – thus displaying the temperature.
Temperature gauges measure the thermal state of a homogeneous substance. The measuring system must be brought as closely together as possible with the body to be measured. The most widely used measuring methods for temperature measurement rely on temperature-dependent characteristics of the body and substance.