Duo-lateral effect detectors provide a continuous analog output proportional to the displacement of the centroid of a light
spot from the center, on their active area. In this study, first of all the information about lateral effect detectors, some
basic concepts about utilisation of the duo-lateral detectors, lenses have given and the mechanical parts which are
necessary for making optical design verification tests of this system has been introduced. Then, experimental results have
compared with theoretical results.