According to the usage, determine the required output voltage and current; the size of the power supply, the installation method and the installation hole location; there are several outputs, whether each output needs to be electrically isolated; the input voltage range; according to the ambient temperature, determine the drop The amount of power, the power of the power supply; whether certification and safety standards are required; the cooling method of the power supply: natural cooling or forced air cooling; electromagnetic compatibility standards.

1. Select the required safety regulations and electromagnetic compatibility (EMC) certification.

2. Try to use the standard power supply of the power adapter manufacturer, including the standard size and output voltage. In this way, the delivery time is relatively fast; on the contrary, the special size and output voltage will extend the delivery time and increase the cost.

3. In addition, it is necessary to consider the working environment temperature of the power supply, and whether there is additional auxiliary heat dissipation equipment, and the power supply needs to be derated in the excessively high ambient temperature power supply. Refer to the derating curve of ambient temperature to output power.

4. Select the appropriate input voltage range. Taking AC input as an example, the commonly used input voltage specifications are 110V, 220V, so there are correspondingly three specifications of 110V, 220V AC switching, and universal input voltage (AC: 100V-265V). The input voltage specification should be selected according to the area of use.

5. Choose the right power. The switching power supply consumes a part of the power during operation and releases it in the form of heat. In order to increase the life of the power supply, it is recommended to choose a model with a 30% more output power rating.