A photosensor is a device that converts an optical signal into an electrical signal. Its working principle is based on the photoelectric effect. The photoelectric effect means that when light is irradiated on certain substances, the electrons of the substance absorb the energy of the photons and a corresponding electrical effect occurs. According to the phenomenon of photoelectric effect, the photoelectric effect is divided into three categories: external photoelectric effect, internal photoelectric effect and photovoltaic effect. The photoelectric device has a phototube, a photomultiplier tube, a photoresistor, a photodiode, a phototransistor, a photocell, and the like. The performance and characteristic curves of the photovoltaic device were analyzed.
The photosensor generally consists of a processing path and a processing element 2 portion. The basic principle is based on the photoelectric effect, which converts the measured change into a change of the optical signal, and then further converts the non-electrical signal into an electrical signal by means of the photoelectric element. Photoelectric effect refers to the illumination of an object by light. It can be seen as a series of photons with a certain energy being bombarded on the object. At this time, the photon energy is transmitted to the electron, and the total energy of a photon is once The electrons are absorbed, and the state of the electrons is changed by the energy transmitted by the photons, so that the objects irradiated by the light have corresponding electrical effects. Generally, the photoelectric effect is divided into three categories: (1) the phenomenon that electrons can escape from the surface of an object under the action of light is called an external photoelectric effect, such as a phototube, a photomultiplier tube, and the like; (2) an object can be made under the action of light. The phenomenon of resistivity change is called internal photoelectric effect, such as photoresistor, phototransistor, etc.; (3) Under the action of light, the phenomenon that an object generates a certain direction of electromotive force is called photovoltaic effect, such as photocell.
Photoelectric sensors are controlled by converting changes in light intensity into changes in electrical signals.
Photoelectric sensors are generally composed of three parts, which are divided into: transmitter, receiver and detection circuit.
The transmitter is aimed at the target emitting beam, and the emitted beam is generally derived from a semiconductor light source, a light emitting diode (LED), a laser diode, and an infrared emitting diode. The beam is emitted uninterrupted or the pulse width is varied. The receiver is composed of a photodiode, a phototransistor and a photocell. In front of the receiver, optical components such as lenses and apertures are mounted. Behind it is a detection circuit that filters out the valid signal and applies the signal.
In addition, the structural elements of the photoelectric switch also include a launching plate and an optical fiber.