Electronic weighing apparatus
An electronic weighing apparatus includes a switch mounted on a base surface thereof, actuated by an actuating member biased to support a portion of the base. When weight is applied to the apparatus, the actuating member is moved to a depressed position, thereby automatically energizing the apparatus. In addition, a tab is mounted to the base near the switch. Vertical forces can be applied to the tab to depress the actuating member without disturbing the zero position of the weighing apparatus. Furthermore, the apparatus includes an optical coded disc with a plurality of concentric code tracks. A light guide conducts light to a line on the disc which is parallel to but offset from a radius of the disc. Photosensors are positioned on the other side of the disc, opposed to the light guide. A mask is interposed between the photosensors and the light guide, which mask defines a plurality of apertures, each of which is oriented parallel to a radius of a respective code track such that no two of the apertures are parallel.