Plant extracts

A switched-mode power supply is an electronic power supply unit that incorporates a switching regulator. While a linear regulator maintains the desired output voltage by dissipating excess power in a pass power transistor, the switched-mode power supply switches a power transistor between saturation and cutoff with a variable duty cycle whose average is the desired output voltage. It switches at a much-higher frequency than that of the AC line, which means that the transformer that it feeds can be much smaller than one connected directly to the line/mains. Switching creates a rectangular waveform that typically goes to the primary of the transformer; typically several secondaries feed rectifiers, series inductors, and filter capacitors to provide various DC outputs with low ripple.