A photosensor arrangement produces an electrical signal responsive to the position of a source of light by employing a mask (15) situated at a predetermined height above a plurality of photodetectors (D1,1), (D1,2), (D2,1), (D2,2) such that as the sun moves with respect to the apparatus, a shadow is cast which is responsive to the location of the sun. An apparatus constructed in accordance with the invention has a plurality of photosensors, each having a respective substantially planar light-sensitive surface for receiving the input light from the sun over a predetermined range of positions. In a preferred embodiment where compactness is desired, the planar light-sensitive surfaces are arranged in a substantially coplanar relationship with respect to one another. The light mask, which has opaque (16) and transparent (17) portions, is arranged to overlie the substantially planar light-sensitive surfaces for determining the position-responsive sensitivity characteristic of the apparatus. In certain embodiments, a diffuser is interposed between the light mask and the photodetectors. The response characteristic of the apparatus can be determined by geometric analysis, or empirically using values which may be stored in a look-up table.