In a workshop or laboratory, precision power supplies are essential for measurement, testing and other troubleshooting of electronic circuits and equipment. These laboratory power supplies transform, rectify and regulate the voltages and the output currents, so that measurements can be made without deterioration of the elements to be tested, components, circuits, or complete subassemblies . At a time when equipment performance and energy efficiency are at the center of concerns, there are more and more systems dedicated to the acquisition and analysis of power signals. Just as power supplies no longer simply deliver a constant current and voltage level but simulate the operation of a battery.