Samenvatting
A study was conducted of the poor performance and quality of cheap thermal photo-electric controls in street lighting. The three main recommendations were a) manufacturers should aim for an inverse switching of ½: 1; b) quality of manufacturer, calibration and operation should be improved; and c) an electric photo-control should be developed at an economic price. One type of electronic photo-control-the Horstman EL 10 model is described in detail.