Medium- and low-power DC voltage- and current-stabilized power source made by ring transformer

The utility model discloses a DC power source. The utility model comprises a circular type transformer, a gear shifting circuit, a gear shifting control unit, a rectifying and filtering unit, a series regulating unit, a current sampling unit, a current amplification unit, a voltage stabilizing and current stabilizing automatic switching unit, a current stabilizing control unit and a voltage stabilizing control unit. The gear shifting circuit, the rectifying and filtering unit, the serial regulating unit and the current sampling unit are connected in series orderly, the output of the DC power source is connected with the input of the gear shifting control unit and the input of the voltage stabilizing control unit, the output of the gear shifting control unit controls the gear shifting circuit, the output of the current sampling unit is connected with the input of the current stabilizing control unit, the input of the voltage stabilizing and current stabilizing automatic switching unit is connected with the output of the voltage stabilizing control unit, and the output of the voltage stabilizing and current stabilizing automatic switching unit is connected with a control end of the series regulating unit. The power source has the advantages of small size, light weight, high efficiency, convenient installation and simple circuit.