Photocells

Excelitas' Photocells, or Light-Dependent Resistors, can provide a very economical and technically superior solution for many applications where the presence or absence of light is sensed (digital operation) or where the intensity of light needs to be measured (analog operation).

Semiconductor light detectors can be divided into two major categories: junction and bulk-effect devices. Bulk-effect photoconductors have no junction; their bulk resistivity decreases with increasing illumination, allowing more photocurrent to flow. Signal current from the detector can thus be varied over a wide range by adjusting the applied voltage. Excelitas refers to its photoconductors as photoconductive cells or simply Photocells.

Key Features of Excelitas Photocells include:

    * Lowest-cost visible detector
    * Available in low-cost plastic-encapsulated packages as well as hermetic packages (TO-46, TO-5, TO-8)
    * Responsive to both very low light levels (moonlight) and to very high light levels (direct sunlight)
    * Wide dynamic range: resistance changes of several orders of magnitude between “light” and “no light”
    * Low noise distortion
    * Maximum operating voltages of 50-400V are suitable for operation on 120/240 VAC
    * Easy to use in DC or AC circuits
    * Usable with almost any visible or near-infrared light source