Photodiodes are semiconductor devices that convert light energy into electrical current when exposed to photons. They are used in optical sensors to detect and measure light intensity, wavelength, or radiation levels in various applications. Photodiodes offer high sensitivity, fast response times, and wide spectral ranges, making them suitable for diverse sensing tasks such as ambient light sensing, optical communication, and spectroscopy. In electronic systems, photodiodes are often integrated into optical sensors for applications requiring precise light detection and measurement, including imaging, barcode scanning, and remote sensing. They play a crucial role in enabling optical sensing technology across industries, from telecommunications to biomedical instrumentation.