Electrorheological fluids undergo a phase change between Newtonian and thixotropic (Bingham Plastic) with the application of an electric field having a field strngth in the killovolt/mm range.

A BMBF funded research project resulted in tactile displays using this principle. Several degrees of tactor stiffness could be achieved for varying input voltages controlled optically by means of a GaAs photosensor matrix.