) input type and output voltage
Note: AC is alternating current, DC is direct current, such as AC/DC is alternating current input and direct current output.
The commonly used input voltage specifications are 110V, 220V, so there are three specifications of 110V, 220V AC switching, and universal input voltage (AC: 85V-264V). The input voltage specification should be selected according to the region of use.
2) Switching power supply function
① Regulated switching power supply: the input voltage and output voltage are rated at a certain value; ② thyristor 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 through potentiometer, etc. to adjust.
3) Switching power supply load characteristics
In order to improve the reliability of the system, it is recommended that the switching power supply work at 50%-80% load, that is, 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 is large when the power is turned on, and a suitable power supply should be selected to avoid overload. If the load is a motor, the voltage inversion during shutdown should be considered.
4) Switching power supply power
The long-term full-load use of the switching power supply will affect its life. Therefore, when selecting the power supply, it is recommended to choose a model with an output power rating of 30% more.
5) Ambient temperature
In addition, it is necessary to consider the working ambient temperature of the power supply, and whether there are additional auxiliary cooling devices, and the power supply needs to derate the output when the ambient temperature is too high. Refer to the derating curve of ambient temperature to output power.
