The sensor is generally composed of three parts: sensitive element, conversion element and conversion circuit:

1. Sensitive element (Sensitive element): An element that directly senses the measured value and outputs a certain physical quantity that has a definite relationship with the measured value.

2. Transduction element: It takes the output of the sensitive element as input and converts the input into circuit parameters.

3. Transduction circuit: The above circuit parameters can be converted into power output by connecting to the conversion circuit.

In fact, some sensors are very simple, consisting of only one sensitive element (doubling as a conversion element), which directly outputs electricity when it senses the measured value. such as thermocouples.

Some sensors are composed of a sensitive element and a conversion element without a conversion circuit.

For some sensors, there is more than one conversion element, which needs to be converted several times.