What is the usage and purpose of DC power supply
Release time：2020-01-09 Clicks： Click
What is the usage and use of DC power supply? We will give you a detailed introduction in the following details.
DC power supply is DC power supply, which is a device to maintain a stable current in the circuit. Such as dry battery, battery, DC generator, etc.
The DC power supply has two electrodes, positive and negative. The potential of the positive electrode is high and the potential of the negative electrode is low. When the two electrodes are connected with the circuit, they can maintain a constant potential difference between the two ends of the circuit, thus forming a current from the positive electrode to the negative electrode in the external circuit.
The stable water flow can not be maintained only by the difference of water level, but can be maintained by means of the pump continuously sending water from the low place to the high place. Similarly, the electrostatic field generated by the charge alone can not maintain a stable current, and with the help of DC power supply, the non-static action (referred to as "non-static power") can be used to make the positive charge return from the negative electrode with lower potential to the positive electrode with higher potential through the power supply, so as to maintain the potential difference between the two electrodes, thus forming a stable current. Therefore, DC power supply is a kind of energy conversion device, which converts other forms of energy into power supply circuit to maintain the steady flow of current.
The non-static power in the DC power supply is from the negative to the positive. When the DC power supply is connected with the external circuit, the current from the positive to the negative is formed outside the power supply (external circuit) due to the promotion of the electric field force. In the power supply (internal circuit), the non electrostatic force makes the current flow from the negative to the positive, so that the charge flow forms a closed cycle.
The electromotive force of the power supply is an important characteristic of the power supply itself. It is equal to the work of the non electrostatic force when the unit positive charge moves from the negative to the positive through the power supply. When the power supply provides energy to the circuit, the power P supplied is equal to the product of the electromotive force E of the power supply and the current I, P = EI. Another characteristic quantity of the power supply is its internal resistance (referred to as internal resistance) R0. When the current passing through the power supply is I, the heat power (Joule heat generated in unit time) of the internal loss of the power supply is equal to r0i.
When the positive and negative poles of the power supply are not connected, the power supply is in the open circuit state. At this time, the potential difference between the two electrodes of the power supply is equal to the EMF of the power supply. In the open circuit state, there is no mutual conversion between non electric energy and electric energy. When the load resistor is connected to the two poles of the power supply to form a closed circuit, the current inside the power supply flows from the negative pole to the positive pole. At this time, the power e I provided by the power supply is equal to the sum of the power U I delivered to the external circuit (U is the potential difference between the positive pole and the negative pole of the power supply) and the thermal power r0i lost in the internal resistance, e i = u ir0i. Therefore, when the power supply provides power to the load resistor, the potential difference between the two poles of the power supply u = e-r0i.
When another power supply with larger electromotive force is connected to the power supply with smaller electromotive force, the positive pole is connected to the positive pole, and the negative pole is connected to the negative pole (for example, charging the battery with a DC generator), the current flows from its positive pole to the negative pole in the power supply with smaller electromotive force. At this time, the external boundary inputs the electric power U I to the power supply, which is equal to the energy E I and internal resistance stored in the power supply in unit time Sum of thermal power r0i of medium loss, u i = e ir0i. Therefore, when the external power input to the power supply, the external voltage added between the two poles of the power supply should be u = er0i.
When the internal resistance of the power supply can be ignored, it can be considered that the EMF of the power supply is approximately equal to the potential difference or voltage between the two poles of the power supply.
In order to obtain high DC voltage, the DC power supply is often used in series. At this time, the total EMF is the sum of the EMF of each power supply, and the total internal resistance is also the sum of the internal resistance of each power supply. Due to the increase of internal resistance, it can only be used in circuits with low current intensity. In order to obtain a larger current intensity, the DC power supply with equal electromotive force can be used in parallel. At this time, the total electromotive force is the electromotive force of a single power supply, and the total internal resistance is the parallel value of the internal resistance of each power supply.
There are many types of DC power supply. In different types of DC power supply, the nature of non-static power is different, and the process of energy conversion is also different. In chemical batteries (such as dry cells, batteries, etc.), non-static power is a chemical action associated with the dissolution and deposition process of ions. When chemical batteries are discharged, chemical energy is converted into electrical energy and Joule heat. In thermal power sources (such as metal thermocouple, semiconductor thermocouple), non-static power is a diffusion action associated with temperature difference and electronic concentration difference. The thermal power source is outward When the circuit provides power, the heat energy is partially converted into electrical energy. In the DC generator, the non-static power is electromagnetic induction. When the DC generator supplies power, the mechanical energy is converted into electric energy and Joule heat. In photovoltaic cells, non-static power is the function of photovoltaic effect. When photovoltaic cells supply power, light energy is converted into electric energy and Joule heat.
1. Sophisticated electrolytic capacitor, tantalum capacitor enabling
2. Sophisticated electronic components such as resistor, relay and motor, routine test
3. Laboratory, electronic equipment, automatic testing equipment
4. Electronic inspection equipment, production line equipment, communication equipment
5. All other occasions requiring DC power supply