The aim of this research is to design and construct Kerr electro-optic cell with a pulse generator which is necessary for the operation of the cell, and studying the use of the cell in laser modulation. A He-Ne laser was used as a light source. The cell was constructed in a simple method of Pyrex glass with two aluminum electrodes, which both are inexpensive comparing with other designs. The pulse' generator was designed to produce variable duration high voltage-rectangular pulses. At the beginning, nitrobenzene has been chosen v as the electro-optical medium, but then we didn't do because there are some disadvantages in its use. However, several organic liquids have been used instead of it, among them was benzaldehyde and acetophenone. The Kerr constants for all liquids were measured. Also, the variation of the induced birefringence with the applied field and the amplitude modulation were studied. It was found that the values of the kerr constants of the solvents, which were measured at wavelength 632.8 nm, are somewhat in agreement with other measurements for various investigators, except" those of the two above solvents, since their published Kerr constants were measured by one investigator, at wavelength 564.4 nm. Although Kerr constant of nitrobenzene is larger than Kerr constants of dill other used solvents, which causes more transmission of light through nitrobenzene than others, the acetophenone and the benzaldehyde, which have rather large Kerr constants, are more suitable to use than nitrobenzene, to avoid disadvantages of in the amplitude modulators using it, and than other liquids, for their small Kerr constants.