An electronic voting system with a headquarters unit, a plurality of precinct units, a plurality of voting stations associated with each precinct unit, and a plurality of mobile memory units to contain data that can be transported back and forth between the headquarters unit and the precinct units. With the compound, it is possible to provide a polyimide which shows no absorption in the ultraviolet region and is highly transparent to light, has high insulating properties, has improved heat resistance and processability, and has excellent solubility in organic solvents. The semiconducting layer includes a carbon nanotube structure comprised of carbon nanotubes. In addition a suitable device for the evaluation of the signals of a sensor is proposed. An analog voltage is then applied to the sub-frames to produce a reduced grayscale. Thus, it increases the anti-interference ability of the circuit, and may be widely used in situations of data communication through AC power lines.