Reverse polarisation technique

This technique is used to measure spontaneous polarisation and switching time. For spontaneous polarisation a low frequency triangular/ square wave is applied to the sample cell containing liquid crystal. The thickness of the cell is in he range of micrometers. The voltage of the applied wave is nearly 40-50 Vpp. This is obtained by a low frequency amplifier. The output current response is observed in the digital oscilloscope. The response due to polarisation has a characteristic hump. The area under the curve gives the corresponding polarisation.

Schematic diagram of setup

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