The working principle of ldr sensor is based on the internal photoelectric effect. Electrode leads are installed at both ends of semiconductor photosensitive material and packaged in the shell with transparent window to form ldr sensor. In order to increase sensitivity, the two electrodes are often made into combs. The materials used to make idr sensor are mainly semiconductor, such as sulfides, selenides and tellurides of metals and so on.
Usually, thin ldr sensor and comb-shaped ohmic electrodes are fabricated on insulating substrates by coating, spraying and sintering methods. Leads are connected and encapsulated in sealed shells with transparent mirrors to avoid dampness affecting their sensitivity.
When the incident light disappears, the electron hole pairs generated by photon excitation will recombine, and the resistance value of the ldr sensor will restore to its original value. A voltage is applied to the metal electrodes at both ends of the ldr sensor, in which the current passes through, and the current will increase with the increase of the intensity of light when irradiated by a certain wavelength of light, thus realizing photoelectric conversion.
Ldr sensor has no polarity. It is purely a resistor device. It can be used with both DC voltage and AC voltage. The conductivity of semiconductor depends on the number of carriers in the conductor band.
Ldr sensor is a semiconductor photosensitive sensor. It has the characteristics of high sensitivity, fast reaction speed, good spectral characteristics and R value. It can also maintain high stability and reliability in high temperature and humid environment.
It can be widely used in optical automatic switch control field, such as camera, solar energy, yard lamp, lawn lamp, money checker, quartz clock, music cup, gift box, mini night lamp, photoacoustic switch, street lamp automatic switch and various light-controlled toys, light-controlled lights, lamps and lanterns and so on.