A diaper changing table is a piece of furniture with a pad on top, two rods with stirrups and a foot pedal that raises the rods. The logic may be configured to increment the gain in response to digital gain control signals or an analog gain control signal. The inner holding member supports the optical element by use of one pair of the pieces, which are disposed opposed to each other, in which one pair of the driving units of the inner holding member is disposed opposed to each other and provided on the inner holding member at two points. A medium voltage DC collection network comprises positive pole cables and negative pole cables, wherein each positive pole cable is connected to the positive DC voltage output of a first active rectifier and each negative pole cable is connected to the negative DC voltage output of a last active rectifier.