Diode devices are disclosed in which the separation of the electrodes is set and controlled using piezo-electric, electrostrictive or magnetostrictive actuators. The class-D PWM modulator includes a differential output driver configured for driving a first and a second output signals in response to the first and the second PWM signals. The outer surface of the fluoroplastic sleeve is roughened to a surface roughness of between about 0. A handle secured adjacent the upper part of the cabinet allows to pull or push the cabinet when required.