How do Photo Detectors function?

Photo detectors function by sensing changes in reflected light. They are devices that convert light energy into electrical signals. This transformation occurs when light photons strike the surface of the photo detector, leading to a change in the material's conductivity or generating a current.

The operation of photo detectors is based on principles of optics and electronics, where the intensity, wavelength, or other characteristics of the light can result in variations in the output signal. This capability makes them essential in various applications, such as cameras, solar cells, and communication systems, where light detection is necessary for functionality.

Other options do pertain to different types of sensing mechanisms but are not applicable to photo detectors. Measuring distance typically relates to technologies like LIDAR or ultrasonic sensors, detecting temperature changes is aligned with thermometers or thermal sensors, and measuring sound vibrations involves microphones or acoustic sensors.