Abstract: A circuit board and a method of making same having a plurality of conductor lines wherein at least one portion of at least one line is superimposed over a portion of at least one other line to define at least one intersection. A substrate is provided of insulating material and a first insulating coating is applied to at least one side of the substrate. A first set of conductive nonintersecting lines is applied to the varnished coating and a coating of insulating varnish is applied on and around the conductive lines only in the vicinity of the intersection. A second set of nonintersecting conductive lines define the intersection with the first set by being applied onto the substrate. The circuit board may be used in a multiple circuit keyboard switch assembly. A conventional type pushbutton bridging contact array selectively interconnects conductor lines at particular switch sites.

Abstract: A trimming potentiometer in which three parallel resistance paths are located in a plane on an insulating plate. Wiper contacts are displaceable in the same direction on the resistance paths, and are attached to a common carrier which is longitudinally displaceable by a threaded spindle. Inductance loops are arranged between the resistance paths and the respective terminals for the paths, for the purpose of matching the trimming potentiometer to its inductance and capacitive input and output values.