Thermal resistance can be divided into three kinds of lead the way

A, two wire: mainly in the field of thermal resistance on both ends of a wire connection respectively, the resistance of the signal leads directly, we can call two wire; This kind of lead on the way is simple, but because of the connection wire resistance of lead, and on the size and length of the wire and material have relations, so this kind of lead the way is suitable for use in the measurement accuracy is required. Two or three wire system: need to heat resistance, root end directly connect a root lead, while the other side needs to connect two fuses, so we call it a three wire system, this way of lead of commonly used way is a bridge of form a complete set, you can compare effective to eliminate the resistance of the influential factors, lead in industrial process control, is for common use. Three, four wire: because in the ends of the thermal resistance of the roots, respectively connected to the two different conductor, this way could be called a four wire system, there are two main lead is to provide thermal resistance is constant current, and then convert it directly into the voltage signal, eventually again by two other influence to to turn it into a secondary instrument. So this way can lead is very effective to eliminate the influence of the lead, commonly used in the relatively high precision temperature detection.