In the plastic transistor pictured here, the plastic is molded into interdigitated electrodes, which one sees as yellowish-orange bars in this image. These electrodes permit the flow of current to and from the active channel, which is green in this image. This transistor is made using a very low-cost process in which the electrodes are deposited from a water-based formulation; the conductivity of the electrodes is subsequently increased by exposure to a strong acid.