Discussion on “dimmers for tungsten lamps” (Waller) New York, February 18, 1915. (see proceedings for February, 1915)

Leonard Kebler: In Mr. Waller´s paper, he refers to the necessity of the contact shoes moving smoothly over the contacts, and also to the necessity for having easy mechanical movement. In designing a dimmer to get proper change in theatre lighting, the first requisite is the proper proportioning of the resistance, as described by Mr. Waller. After this is done, the mechanism that actuates the resistance controlling arm, and the friction between the moving arm and the stationary contact, pivots, etc., must be such that the arm can be moved over the contact evenly with a minimum of effort on the part of the operator.