| 摘要 |
<p>PURPOSE:To eliminate influence due to the leak resistance of a Pockels effect element, by changing over a pair of electrodes arranged on the same plane of a Pockels effect element to earth potential at a predetermined change-over anglar velocity. CONSTITUTION:Light passing through a Pockels effect element 10 is modulated in proportion to the intensity of an electric field corresponding to voltage Ex to be measured and the length of the advance passage of light passed through the element 10. In this case, switches 61, 62 are alternately driven and electrodes 51, 52 are alternately brought to earth potential to alternately change over electric lines of force acting on the element 10. When a change-over speed omega reaches so as to satisfy formula jomegaC>>1/R (wherein R is leakage resistance and C is capacitance), the influence of the leak resistance of the element 10 is eliminated and impedance from the standpoint of voltage Ex to be measured is not changed even when A.C. or D.C.</p> |
