Optical sensors, including photo detectors and CdS cells, play a significant role in light detection and measurement. These sensors are widely used in applications such as ambient light sensing, photometry, and light-activated switching.

They work by converting light into an electrical signal, with CdS (Cadmium Sulfide) cells being particularly popular for their sensitivity to visible light and cost-effectiveness. These sensors offer reliable performance with a broad spectrum response, making them versatile for various industrial and consumer applications.

Major manufacturers like Advanced Photonix, OSRAM, and Excelitas provide a variety of optical sensors and CdS cells, ensuring solutions that meet specific requirements regarding sensitivity, wavelength range, and response time.