DC Power Honing   supply has positive and negative two electrodes , the high potential of the positive electrode , the negative electrode potential is low, when the two electrodes connected to the circuit after the circuit between the two ends to maintain a constant potential difference is formed in the external circuit to the cathode the negative electrode current.
 The difference between the water level alone can not maintain steady flow , while continuing to help pump water from the lower to send uphill to maintain a certain level difference can form a steady flow of water . Similarly , alone electrostatic field generated by the charge can not maintain a steady current, and DC power supply means , you can use the non-electrostatic effect ( referred to as "non- static electricity " ) to the positive charge at the cathode of the lower potential the internal power supply to return to the positive electrode at a high potential , in order to maintain the potential difference between two electrodes , thereby forming a steady current. Therefore, a DC power source is an energy conversion device , which the other forms of energy is converted to electric energy supply circuit to maintain a steady current flow.
DC power in a non- static electricity is generated by the negative point cathode . When the DC power supply and the external circuit is turned on, the power supply external ( external circuit ) , as driven by the electric force , formed by the cathode to the anode current. In the internal power supply ( internal circuit ) , the role of the non- static electricity so that current flows from the negative electrode a positive electrode, so that the flow of charge to form a closed loop. Linear regulated DC power supply steady flow
Performance of the power supply itself is a significant amount of power of the force characteristic , which is equal to unit charge from the negative electrode to move the positive electrode through the power supply internal work done by non- static electricity . When the power supply provides energy to the circuit when the power P is equal to the supplied power of the force E and the current I between the product , P = EI. Another feature of the amount of power to its internal resistance ( short resistance ) R0, when the current I through the power , the power loss of internal heat power ( per unit time, the Joule heat generated ) is equal R0I.
When the power of the positive and negative poles is not connected , the power supply in the off (open ) state, then the power supply potential difference between two electrodes is equal in magnitude on the power of the force . In the circuit state does not occur with non- electric energy conversion. When the load resistor connected to the power poles to form a closed loop , through the internal power supply current to flow from the negative cathode , then , the power provided by the power delivered to the external circuit EI equal to the power of UI (U is the positive power supply and potential difference between the anode ) and the heat dissipated in the internal resistance of the power R0I , EI = U IR0I. Thus , when the power supply to provide power to the load resistor , the power supply potential difference between the poles U = E-R0I.