The working principle of photovoltaic sensor:
Photovoltaic effect is short for photovoltaic effect. It refers to the phenomenon that an object generates electromotive force after being illuminated. Photovoltaic cell is a kind of self-generating photoelectric component, which can generate a certain direction of electromotive force when it is illuminated. Without power supply, as long as the external circuit is connected, there will be current passing through. The specific working principle is as follows:
A large area PN junction is formed by diffusion of some P-type impurities into a N-type silicon wafer. There are a lot of holes in the P-region and a lot of electrons in the N-region. When light irradiates the surface of P region, if the photon energy is larger than the forbidden bandwidth of silicon, an electron-hole pair will be generated for each photon absorbed in P region. The more photons absorbed on P region, the more electron holes excited, and the fewer electron holes will be absorbed towards PN junction.
The role of photovoltaic sensors:
It can be used to detect the non-electric quantity which directly causes the change of light quantity, such as light intensity, illumination, radiation temperature measurement, gas component analysis, etc. It can also be used to detect other non-electric quantity which can be converted into the change of light quantity, such as the diameter of parts, surface roughness, strain, displacement, vibration, speed, acceleration, and the identification of shape and working state of objects.
