Character display for electronic weighing scales - with each character group comprising seven LED segments connected to transistors and common current source

摘要

The character display, e.g. for electronic weighing scales, has each character group formed by 7 light-emitting diode segments, one end of each segment connected to the other segments of the group and the other end connected via a conductive path to similar segments of the other character groups. The similar ends of the segments are connected to collector electrodes of respective transistors the emitter of each transistor connected to a common current source. The bases of the transistors are connected to corresponding outputs of character selection means, which are controlled by counters. The conductive paths between the segments of the different groups are connected via further conductive paths with corresponding comparator inputs the comparators also connected via resistors to the emitter electrodes of the transistors and via further resistors to corresponding decoder outputs.