In this meaning, DC is short for direct current: electricity that flows one way and keeps going that way. A battery gives DC. The power inside a phone, a laptop, and most small electronics is DC.

In this meaning在這個意思裡，DC is short for是 direct current 的縮寫： electricity電 that flows one way往一個方向流， and keeps going that way而且一直往那個方向。 A battery電池 gives給的是 DC。 inside a phone, a laptop, and most small electronics手機、筆電和大多數小電器裡面的 The power電 is DC就是 DC。

The other common kind is AC, alternating current — what comes out of a wall socket in a house, switching direction many times a second. A charger exists because the wall gives AC, and the machine wants DC.

The other common kind另一種常見的 is AC是 AC， alternating current—— what comes out of a wall socket in a house家裡牆壁插座出來的那種， switching direction方向切換 many times a second一秒好多次。 A charger充電器 exists because會存在，是因為 the wall牆壁 gives AC給的是 AC， and而 the machine機器 wants DC要的是 DC。

Though actually, the letters DC are famous for other things too (a city, a comics company), but this entry is only the electricity meaning. Technical, but very common once you talk about plugs and batteries.

Though actually不過其實，the letters DC DC 這兩個字母 for other things too也因為別的東西 are famous出名（ a city一座城市、 a comics company一家漫畫公司）， but但 this entry這個條目 is only只講 the electricity meaning電的意思。 Technical屬於技術詞， but但 once you talk about只要談到 plugs and batteries插頭和電池 very common就非常常見。