Catalogues : Photoresistors | Optocouplers | Optical switch.
Photoresistors are semiconductor elements that change the resistance value depending on the illumination.
TESLA BLATNÁ, a.s. produces standard series of photoresistors with spectral sensitivity in the range of 530 - 720 nm, (typical values of power dissipation from 125 to 500 mW and values of operating voltage from 150 to 1 500 V) and with various types of encapsulation. These are encapsulated in a glass flask (type G09), oval ceramic insert itself (types K11, K25), metal housing (types M08), ceramic insert in plastic (types P13, P28) and rectangular ceramic insert itself (type S44).
The photosensitive materials used make it possible to change the wavelength for maximum sensitivity in the range 510-730 nm (abbreviated as 53,56,60,65,72 in the type designation). Dependence of resistance on illumination is given by tabulated values of resistance at illumination of 10 lx (in the type designation the center of the tolerance field of resistance values, eg as 10,15,20,40).
An optocoupler with a photoresistor is an optoelectronic coupler consisting of a light-tight encapsulated electroluminescent LED, optically coupled to the photoresistor. The optron is encapsulated in a plastic housing and serves to transmit a signal between two galvanically isolated circuits. Unlike conventional optocouplers with a phototransistor, triac, the optocoupler with a photoresistor behaves like an electrically controlled potentiometer, where the resistance of the photosensitive layer depends on LED illumination. Optocouplers are characterized by low non-linear distortion (THD 0.025-0.035%). The types of optrons with dual photoresistor at the output are characterized by shorter rise and fall times and defined signal symmetry. Optocouplers with photoresistors are used, for example, in audio technology and instrumentation. Examples of applications are circuitry to protect the speakers against overload, current power control-limiters, silent input switching, stereo gain control, tunable filters, gain control of electronic amplifiers.