Voltage regulator is the autoconnected transformer that the turn ratio can be adjustedcontinuously. When turning the hand, it slides on the polished surface of the coil with the aid of the moveable brush to change the trun ratio. So then the output voltage can be adjusted smoothly from zero to the maximum value.
ADD: Liushi Town, Yueqing City, Zhejiang Province,P.R. CHINA 325604