What is the lead out method of thermal resistance

What is the lead out method of thermal resistance
There are three ways to lead out thermal resistors: 2-wire system, 3-wire system, and 4-wire system.
A, The wiring of 2-wire heating resistors is simple, but it requires additional errors in the lead resistors. Therefore, it is not suitable for manufacturing A-grade precision thermistors, and the leads and wires should not be too long during use.
B, The 3-wire system can eliminate the influence of lead resistance and has higher measurement accuracy than the 2-wire system. As a process detection component, it has the widest application.
C, The 4-wire system can not only eliminate the influence of lead resistance, but also eliminate the influence of the same resistance when connecting wires with the same resistance. When measuring with high precision, a 4-wire system should be used.
The temperature measurement principle of thermal resistance is based on the characteristic that the resistance value of a conductor or semiconductor changes with temperature to measure temperature and temperature related parameters. Thermistors are mostly made of pure metal materials, with platinum and copper being the most commonly used. Currently, materials such as nickel, manganese, and rhodium have been used to manufacture thermistors. Thermistors typically require the transmission of resistance signals through leads to computer control devices or other secondary instruments.
There are four types of thermal resistors:
1, Ordinary type thermistor
According to the temperature measurement principle of thermal resistance, the change in the measured temperature is directly measured through the change in the resistance value of the thermal resistance. Therefore, the change in resistance of various wires such as the lead wires of the thermal resistance body will have an impact on temperature measurement.
2, Armored thermistor
Armored thermistor is a solid body composed of temperature sensing elements (resistors), leads, insulation materials, and stainless steel sleeves. Its outer diameter is generally between 2 and 8mm, and the minimum can reach 0.25mm. Compared with ordinary thermistors, it has the following advantages:
1. Small size, no air gap inside, thermal inertia, small measured value;
2. Good mechanical performance, vibration resistance, and impact resistance;
3. Can bend, easy to install;
4. Long service life.
3, End face thermistor
The end face thermistor temperature sensing element is made of specially processed resistance wire wound tightly against the end face of the thermometer. Compared with general axial resistance thermometers, it can more accurately and quickly reflect the actual temperature of the measured end face, and is suitable for measuring the end face temperature of bearing shells and other components.
4, Explosion proof thermistor
Explosion proof thermistor uses a special structure of junction box to confine the explosion of explosive mixed gas inside its shell caused by sparks or arcs within the junction box, so as not to cause excessive explosion in the production site. Explosion proof thermal resistors can be used for temperature measurement in areas with explosive hazards within Bla-B3c level zones.