選擇正確的電源適配器

　　電子設備是我們現代世界中經常出現的一部分，所有電子設備共享的一件事就是對電力的需求。一些電子設備是由電池供電，而另一些依靠墻壁適配器。各種設備的直流電壓，可以通過使用壁適配器轉換成一個給定的設備的直流電壓從一個典型的壁出口成一個直流電壓操作。有許多問題可以用來確定哪一個壁充電器將工作的設備。

　　選擇電源適配器的一些電氣考慮的電壓，該設備將在操作，該設備的當前要求，以及最大輸出功率，您的適配器將需要能夠提供。

　　You will want to choose the exact voltage that your device is supposed to operate at. Current and power have a broader range of options when choosing your adapter. You can always go above a given requirement for current and power in an adapter， this is because the current will be a result of the given impedance of the device and voltage. Your device will draw a certain amount of current regardless of how much your adapter can supply. When thinking about output power ratings for an adapter， it is good to remember that the rating is a maximum rating. Using any power supply consistently at its maximum power output will eventually cause damage to the power supply so having an adapter that has a higher rating than you need is a good thing. Another thing to keep in mind is whether your adapter requires a positive center or a negative center. This can usually be determined by the markings on the existing adapter that will look like this：