A magnetically steered electric switch based on nematic liquid crystal-single-wall carbon nanotube dispersions is demonstrated. The device exploits the conductivity anisotropy of nanotubes in combination with the magnetic Freedericksz transition of a nematic liquid crystal. The performance is characterized with respect to the electric measuring field amplitude, frequency and sample cell gap. The dynamic behavior indicates a response time of approximately 4 s, and possible applications for magnetic field sensors are discussed. (c) 2005 Americian Institute of Physics.