Thermocouple and thermal resistance temperature measurement principle

Thermocouple and thermal resistance temperature measurement principle 
The basic principle of the thermocouple to measure the temperature is the thermoelectric effect. The secondary meter is a pedometer or an electronic potentiometer is used to increase the accuracy.

The resistance works based on the characteristics of the resistance of the conductor and the semiconductor as a function of temperature. The secondary meter is an unbalanced bridge.

On-site judgment at work .

1. Thermocouples . Thermocouples have positive and negative poles, and compensating leads also have positive and negative points . First ensure connection and configuration . In operation, common short circuits, open circuits, poor contact ( with multimeter to judge ) and deterioration ( according to Surface color to identify ) . When checking, separate the thermocouple from the secondary table.

2. Thermal resistance. Nothing more than a short circuit, and open circuit. Multimeter can be determined. In operation. Suspected short, just remove the resistor end a thread, see the display instruments, such as the maximum, thermal resistance short circuit. Back to zero, the wire is shorted. When the normal connection and configuration are guaranteed, the table value shows low or unstable, and the protection tube is likely to enter the water. The display is maximum and the thermal resistance is open. Shows minimum, short circuit.