what is the principle of DC power supply

The DC power supply has two electrodes, positive and negative. The positive potential is high and the negative potential is low. After the two electrodes are connected to the circuit, a certain potential difference can be maintained between the two ends of the circuit, thereby forming a positive-to-negative current in the external circuit. A DC power supply is an energy conversion device that converts other forms of energy into electrical energy supply circuits to maintain a steady flow of current.