The insulation resistance of a thermistor element is measured between its lead wires and glass.
It is essential that a thermistor provides good electrical insulation to secure its durability. Shibaura carries out 100% inspection on all products (except PSB-N, RB1-N and KG) by measuring the insulation resistance of each element in manufacturing processes.
The figure below shows the measuring method.
A metal container is filled with conductive liquid. A thermistor is immersed in the liquid in such a way that its glass is submerged below the liquid surface. (For NS elements, the liquid level is on the ceramics.)
The positive pole of the insulation meter is connected to the thermistor lead wires, and the negative pole to the metal container, and the resistance between the lead wires and glass is measured.