Lateral-effect position sensitive photodetectors (PSDs) have received a great deal of attention as an alternative to scanning and array techniques for deriving spatially dependent information from incident radiation, since they have the advantages of instantaneous and fast measurements, greater position resolution, simplicity in circuitry and inexpensive. Basic physics, operation and demanding applications are reviewed. In this paper different experimental techniques which are established to evaluate transfer characteristics, repeatability, sensitivity of a single axis detector UDT SL-76 are presented. The percentage of nonlinearity and the Root Mean Square error have been calculated. An analog processing circuitry for position measurement is designed and presented. The cause of bias variation to the detector, laser beam intensity fluctuation and laser drift during warm-up in position measurements and the minimum intensity required to produce stable position information have also been presented.