A device that exploits the effects that arise due to the quantized nature of charge. They are based on the controllable transfer of single electrons or a few electrons between small conducting and semiconducting clusters. When an electron is added to a small conductor or semiconductor, the voltage increases by a step of e/C, where e is the charge of an electron and C is the total capacitance. This effect can be observed in systems of small metal structures, quantum dots, and nano-scale conducting polymers. See nanodevice.