1. A carbon nanotube system operating as an analog differential amplifier, the system comprising: a carbon nanotube; a first plurality of electrical contacts configured to electrically contact the carbon nanotube; a second plurality of electrical contacts proximate to the carbon nanotube, each separated from the carbon nanotube by at least one insulator so that each electrical contact of the second plurality of electrical contacts exerts an electric field on the carbon nanotube sufficient to cause at least a portion of the carbon nanotube to operate as a field effect transistor.