Investigation of electric field induced elastic deformations of nematic liquid crystals by capacity measurements

An improved set-up is described which is universally applicable in electrooptic research work on liquid crystals. The main part of the test circuit consists of a highly stabilized and dc-free square wave generator with swept amplitude. An additional sine wave modulation with very good linearity up to high voltages allows capacity versus voltage measurements in a large frequency range. Measurements in the nematic phase of ap-disubstituted phenylcyclohexane (PCH) are reported as an example of the high performance of this set-up.