Variable electrical impedances

Claim 1

A VARIABLE CAPCITOR COMPRISING A LIGHT-TIGHT ENCLOSURE, A COMPOSITE MEMBER LOCATED WITHIN SAID ENCLOSURE, SAID MEMBER CONSISTING OF A GLASS CYLINDER, A LAYER OF LIGHT TRANSMISSIVE ELECTRICALLY CONDUCTING MATERIAL SUPPORTED ON THE OUTER SURFACE OF SAID CYLINDER, A LAYER OF PHOTOCONDUCTIVE MATERIAL SUPPORTED ON SAID LAYER OF CONDUCTING MATERIAL, A LAYER OF DIELECTRIC MATERIAL SUPPORTED ON SAID LAYER OF PHOTOCONDUCTIVE MATERIAL AND A LAYER OF CONDUCTING MATERIAL SUPPORTED ON SAID LAYER OF DIELECTRIC MATERIAL, AN ELECTRIC INCANDESCENT LAMP LOCATED WITHIN SAID CYLINDER AND TWO OPAQUE SEMI-CYLINDERS CONCENTRIC WITH SAID LAMP AND POSITIONED BETWEEN SAID AND SAID CYLINDER, ONE OF SAID SEMI-CYLINDERS BEING FIXED AND THE OTHER SEM-CYLINDER BEING ROTATABLE ABOUT ITS LONGITUDINAL AXIS TO PROVIDE A VARIABLE GAP BETWEEN ADJACENT ENDS OF SAID SEMI-CYLINDERS TO ENABLE A BEAM OF LIGHT OF VARIABLE WIDTH TO BE DIRECTED FROM THE LAMP ON TO SAID LAYER OF PHOTOCONDUCTIVE MATERIAL TO PROVIDE A CONDUCTING REGION BETWEEN SAID LAYER OF LIGHT TRANSMISSIVE MATERIAL AND SAID LAYER OF DIELECTRIC MATERIAL.