Wiring method of thermistor bridge

The wiring methods of different electronic devices are different, and the correct wiring method can be guaranteed for performance and service lifetime. What is the wiring method for the thermistor bridge?

In related materials, the thermistor-based bridge thermometer is introduced. The main reason is that the thermistor bridge thermometer has large nonlinearity when it is linearized in a large temperature range according to the general theory (one-step linearization method). error. Usually the thermistor temperature measuring bridge is designed and manufactured under the limited conditions that the thermistor self-heating effect can be ignored. When the output is a current or voltage signal, the sensitivity of the bridge is proportional to its terminal voltage. When the output is a power signal, the sensitivity of the bridge is proportional to the square of the terminal voltage. To prevent self-heating, it is necessary to limit the number of terminals. Therefore, the sensitivity of the bridge is suppressed.

Regarding the self-heating condition of the thermistor, the test data made under the constant temperature of °C. In addition to temperature measurement, self-heating bridges can be used for thermal conductivity gas analysis, micro pressure and small flow measurement. The thermal resistance is a three-wire connection. The three-wire system is used to eliminate measurement errors caused by the resistance of the connecting wires. This is because the circuit for measuring the thermal resistance is generally an unbalanced bridge. The thermal resistance is used as a bridge arm resistance of the bridge. The connecting wire (from the thermal resistance to the central control room) also becomes part of the bridge arm resistance. This part of the resistance is unknown and varies with the ambient temperature, causing measurement errors.

The three-wire system is used to connect one wire to the power supply end of the bridge, and the other two are respectively connected to the bridge arm where the thermal resistance is located and the bridge arm adjacent thereto, thus eliminating the measurement error caused by the wire line resistance. The three-wire system is generally used in the industry. The wiring method of the thermistor bridge is the three-wire connection method. This wiring method ensures the security of the connection and reduces the measurement error caused by unnecessary factors.