Smoothed DC power supplies are unregulated units in which the transformer provides the secondary low voltage. This low AC voltage will be converted by the rectifier into a pulsing DC voltage and afterwards smoothed by electrolytic capacitors. The value of this DC voltage is approximately 1.42 times higher than the transformer secondary voltage. In dependency of the alternating loads the output voltage level will fluctuate accordingly. A great variation of the output voltage can be easily maintained with simple control circuits. The DIN 19240 describes the voltage tolerances clearly for electrical consumers to ensure a problemfree function within the release range.