Abstract: An article, such as a light-emitting diode, for replacing a slide base switchboard lamp has polar characteristics. The article has a light emitting cap located at one end and a cylindrical slide base with two contacts located diametrically across the base extending from the emitter. Handling the articles for testing their light intensity and hue characteristics involves orienting them. The articles are first oriented longitudinally in a vertical direction and to face the emitter all in the same direction. The articles are then conveyed in sequence to a test station. An eccentric force is applied to the base through friction between the moving articles and a stationary ledge. The applied force rotates the articles into one or the other of two oriented positions in which the contacts on the base become located in a plane perpendicular to the direction of their conveyance. A preliminary test determines which of the two positions have been assumed by each article.