Basic working principle of liner power supply
A constant water flow cannot be maintained solely by the difference in water level, but a constant water level difference can be maintained by means of a water pump to continuously send water from a low place to a high place to form a steady water flow. Similar to this, the electrostatic field generated by the charge alone cannot maintain a constant current, but with the help of a liner power supply
, the non-electrostatic effect (referred to as "non-electrostatic force") can be used to move the positive charge from the negative electrode with a lower potential. Return to the positive electrode with higher potential through the power supply to maintain the potential difference between the two electrodes, thus forming a stable current.
The non-electrostatic force in a liner power supply is directed from the negative pole to the positive pole. When the liner power supply
is connected to the external circuit, a current from the positive pole to the negative pole is formed outside the power supply (external circuit) due to the promotion of the electric field force. And inside the power supply (internal circuit), the action of non-electrostatic force makes the current flow from the negative pole to the positive pole, so that the flow of charge forms a closed cycle.
An important characteristic of the power supply itself is the electromotive force of the power supply, which is equal to the work done by the non-electrostatic force when the unit positive charge moves from the negative pole to the positive pole through the interior of the power supply. When the power supply provides energy to the circuit, the supplied power P is equal to the product of the electromotive force E of the power supply and the current I, P=E I. Another characteristic quantity of the power supply is its internal resistance (abbreviated as internal resistance) R0. When the current passing through the power supply is I, the thermal power lost inside the power supply (that is, the Joule heat generated per unit time) is equal to R0I.