A detector is a device used to record the signal in a spectroscopy experiment (or in general). For example, camera film is a type of detector. The coating on the film reacts to the light directed to it by the camera optics and records an image. Digital cameras also have a detector called a CMOS. This is an electronic device that turns light into electrical signal instead of physically changing a surface. A common detector used for spectroscopy is the CCD. They are used for UV and visible experiments. Another type of electronic detector is a PDA, which is used in the NIR.
