According to the ac dc power adaptor company, the nominal voltage of the general power supply refers to the open-circuit output voltage, that is, the voltage when there is no load and the voltage when there is no current output, so it can also be understood that this voltage is the upper limit of the output voltage of the power supply. When an active voltage regulator element is used in the power supply, its output is constant even if the supply voltage fluctuates. If the power supply voltage fluctuates, the output of the power supply will not fluctuate with it.
The ac dc power adaptor company said that in general, the actual no-load voltage of ordinary power adapters is not necessarily the same as the nominal voltage, because the characteristics of electronic components cannot be exactly the same, so there is a certain error, the smaller the error, the more The higher the consistency requirement.

The ac dc power adaptor company explained that there are usually several items on the label of the power adapter that need to be paid attention to:
1. The model of the power adapter. The ac dc power adaptor company takes the model XVE-120100 as an example. It tells us several information, that is, the manufacturer, main parameters, etc. The beginning of XVE is generally the company code, and 120100 means that it is 12V1A Yes, 050200 is 5V2A.
2. The INPUT of the power adapter is generally AC100-240V~50-60Hz in China, which means that the power adapter can work normally under the AC voltage of 100V-240V.
3. The OUTPUT (output) of the power adapter, DC 12V=1A, represents a DC current with a rated voltage of 12V, and the maximum current is 1A. The ac dc power adaptor companies say that these two numbers can quickly calculate the wattage of the power adapter.