Thermal resistor
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When using a thermistor to measure temperature, does the thermistor output current or voltage?
The role of a thermal resistor in temperature measurement is that of a sensor; its output can only be based on its own properties, namely the resistance value
The temperature measurement principle of thermoresistors is based on the property that the resistance value of a conductor or semiconductor changes with temperature, which is used to measure temperature and temperature-related parameters.
A thermoresistor outputs resistance; however, when used for temperature measurement, it is connected to a bridge. A current flows through the measurement circuit, and there are also voltage changes at its two ends.
A thermal resistor is, in essence, a resistor itself. However, when instruments measure this resistor, they almost always use a bridge circuit; by detecting the output of this bridge, that is, by capturing differential voltage signals in the mV range, they can determine changes in the resistance value. In the measurement circuit, the thermal resistor serves as one of the arms of the bridge.
What was mentioned above refers to measuring the thermistor using a bridge circuit in the 2-wire and 3-wire connections. In the 4-wire configuration, 2 wires are used for the mA-level constant current source to flow through the thermistor, while 2 wires are used to measure the mV-level voltage across the thermistor
Therefore, when measuring a thermal resistor, what is actually being measured is a voltage signal in the mV range. What is actually measured is a voltage signal in the mV range. What is actually measured is a voltage signal in the mV range. When you use the resistance setting of a multimeter, its internal circuitry measures voltages on the order of mV as well. . . Do you understand?
The output of a thermoresistor is a resistance, and its value changes in a roughly linear manner with temperature. The thermistor is connected to one of the arms of a Wheatstone bridge; as the temperature changes, the resistance value of the thermistor changes as well, which in turn causes a change in the unbalanced current generated by the bridge. The temperature is determined based on this unbalanced current.
The principle of a thermal resistor is that its resistance changes as the temperature changes; the temperature sensing module converts this resistance signal into a 4-20mA signal for transmission!