For many people, the concept of a power adapter is only limited to the charger stage. Actually, a power adapter is a transformer and applied widely to chargers. People who are unfamiliar with a power adapter have to face selecting which power adapter for charging.

Since power adapters have different parameters, they cannot be used for charging randomly. Three adaption conditions must be determined before selecting a power adapter.

First, interface of an adapter matches with the device;

Second, output voltage must be the same as the rated input voltage of a load (mobile device) or within the voltage range bearable by a load (mobile device); otherwise, the load (mobile device) may be burnt;

Third, output current of a power adapter shall be equal to or greater than current of a load (mobile device) to provide sufficient power;

The following is analysis for three adaptive conditions above.

First, do not insert it in an unmatched interface under the circumstance of no professional knowledge; otherwise, hazard will appear.

Second, in principle, voltage is insufficient to drive a load and a battery cannot charge normally for the reason of unanimous voltage. The popular point of view is supply exceeding demand.

Third, the reason behind the current configuration is needed involves the principle of circuit. It is known that a power has internal resistance; the bigger the internal resistance is, the bigger the loss is. Therefore, the manufacturer will determine the no-load output voltage is within a certain range as per internal resistance during the adapter production. The current critical value corresponding to the voltage critical value is the current nominal value we see. The bigger the nominal value of current is, the better the bearing capacity of the adapter is. Therefore, selecting an adapter with higher current will not damage a battery but speed up charging.