Electrodes of a double-layer capacitor are designed so that sub-capacitors formed at each electrode are stressed substantially equally at the rated voltage of the double-layer capacitor. A movable piston is located in the housing, and a position of the piston is determined by a selected difference between and inlet pressure and an outlet pressure. The signal intensity attenuation for filament-suspended or filament-supported signal lines is much lower than signal lines embedded in solid dielectric materials, allowing for transmission of significantly higher frequency signals within filament-suspended and filament-supported signal lines. The transducer can be either device borne or external.