Abstract: A capacitive pickup device for deriving a measurable voltage which is a linear function of the magnitude of pulsating high voltage of the order of 15 to 40 kilovolts in an insulated conductor, the pickup device having a pair of electrically conducting plate members connected together electrically to form one plate element of a capacitor, the conductor itself forming the other plate element of the capacitor and the conductor insulation forming the dielectric. The pickup device also includes a pair of electrically conducting plates respectively carried in spaced relation with the plate members, the plates being centrally relieved to accommodate the plate members and adapted to be connected to ground.