Physical sensors are sensors that detect physical quantities. It is a device that uses certain physical effects to convert the measured physical quantity into a signal in the form of energy that is easy to process. The output signal has a definite relationship with the input signal. The main physical sensors are photoelectric sensors, piezoelectric sensors, piezoresistive sensors, electromagnetic sensors, pyroelectric sensors, optical fiber sensors, etc. As an example, let us look at the more commonly used photoelectric sensors. This kind of sensor converts light signals into electrical signals. It directly detects radiation information from objects, and can also convert other physical quantities into light signals.
The main principle is the photoelectric effect: when light is irradiated on the material, the electrical effect on the material changes. The electrical effect here includes electron emission, electrical conductivity, and potential current. Obviously, devices that can easily produce such effects become the main components of photoelectric sensors, such as photoresistors. In this way, we know that the main work flow of the photoelectric sensor is to receive the corresponding light irradiation, the light energy is converted into electrical energy through devices like photoresistors, and then through the processing of amplification and noise removal, the required output is obtained. electric signal. The output electrical signal here has a certain relationship with the original optical signal, which is usually close to a linear relationship, so the calculation of the original optical signal is not very complicated. The principles of other physical sensors can be compared to photoelectric sensors.