What is a common use for a photoelectric cell?

A photoelectric cell, often referred to as a photodetector or light sensor, is widely used in applications that require an automatic response to changes in light levels. One of the most common uses for a photoelectric cell is switching street lights.

In this application, the photoelectric cell detects ambient light levels and automatically controls the operation of street lights. When daylight is sufficient, the sensor sends a signal to keep the lights off, conserving energy. As dusk approaches and light levels drop, the cell triggers the street lights to turn on, ensuring that they operate only when necessary. This level of automation enhances safety on the roads and is an efficient use of energy resources. Other potential uses, like regulating power, measuring temperature, or filtering signals, do not align with the primary function of a photoelectric cell.