How to choose a switching power supply?

The following introduces some switching power supply selection tips, so that everyone can avoid detours in the process of selecting switching power supply, and then try to choose regular switching power supply products as much as possible, so that the effect of use will be much better.

Part.1
The first point when choosing a switching power supply is to clarify your needs
Under normal circumstances, we only think about buying a switching power supply when the product we use fails. You can directly take the previous power supply and find some companies that specialize in selling switching power supplies. Is there any model or parameter that matches it? Models that can be replaced can be specifically identified from the following aspects:

1Switching power supply input and output types
It can be roughly divided into: ①AC/DC ②DC/DC ③DC/AC Note: AC means alternating current and DC means direct current. For example, AC/DC means AC input and DC output.
2 input voltage
Commonly used input voltage specifications include 110V, 220V, and universal input voltage (AC: 85V-264V). The input voltage specification should be selected according to the area of use.
3 Output voltage and current
When choosing a switching power supply, the voltage must be the same first, and the current second. The rated current of the switching power supply must be greater than the maximum current of the load. For example, if your circuit is 15V, 60mA, it is generally recommended to choose a power supply above 100mA. In addition, as long as the voltage is the same, no matter how much larger the current provided by the switching power supply is than actually used, only so much will pass through the circuit without any damage.
4 switching power supply function
① Stabilized switching power supply: the input voltage and output voltage are rated at a certain value; ② SCR switching power supply: the output voltage can be changed by adjusting the input voltage; ③ Adjustable switching power supply: within the rated range of the input voltage, the output voltage and current can pass Adjust with potentiometer, etc.
5 Switching power supply load characteristics
In order to improve the reliability of the system, it is recommended that the switching power supply operate at 50%-80% load, that is, choose a model with about 30% more output power rating. For example, if the power used is 20W, a switching power supply with an output power of 25W-40W should be selected. If the load is a motor, light bulb or capacitive load, the current will be large when the power is turned on, so a suitable power supply should be selected to avoid overload.
6Ambient temperature
It is also necessary to consider the working environment temperature of the switching power supply and whether there is additional auxiliary heat dissipation equipment. If the ambient temperature is too high, the power supply needs to derate the output. It is necessary to refer to the derating curve of ambient temperature on output power.

Part.2
The second point when choosing a switching power supply is to choose the right brand.
There are many brands of switching power supplies, and their service life is relatively long, and they are used frequently and for a long time. If the quality of the switching power supply is not high, problems may easily occur. I believe that everyone is more willing to buy high-quality products. Although the price of switching power supplies on the market ranges from tens to hundreds to thousands of yuan, if some non-professionals want to compare the advantages of the products, There is still a certain degree of difficulty in inferiority, so you must choose brand products. The products of big brands or manufacturers have been tested by authoritative departments. The quality of their products is better. Although the unit price is slightly higher, there will not be a big price difference and it is more suitable for us to choose. For example: Taiwan MEAN WELL brand power supply.

Part.3
The third point of choosing switching power supply is to determine after-sales service
The switching power supply can basically be used for several years. Of course, this is only when the purchased product is a regular product that can guarantee a long service life. When purchasing, you must confirm with the seller. If a problem occurs within one month of use, the other party will also provide unconditional replacement with a new product or help us with repairs. It is not recommended to choose non-branded Sanwu products. The quality of such products is likely to have problems and may even threaten our safety. The products of merchants that can provide better after-sales service also have better quality assurance.

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