We investigated the Freedericksz transition in a dual-frequency liquid crystal, in which dielectric anisotropy strongly depends on the frequency of the applied ac electric field. Since the threshold voltage of the Freedericksz transition is a function of the dielectric anisotropy, it was expected that the threshold voltage depends on the frequency. The threshold voltage was determined by observing the Freedericksz transition of liquid crystals under homogeneous, homeotropic, and twisted nematic orientations. In all orientation states, the threshold voltage increased steeply and eventually diverged when the crossover frequency at which the dielectric anisotropy disappeared was approached.
