AC 交流电
DC 直流电
ac: alternating current (缩写 AC)electric current that reverses its direction at regular intervals 交流电
dc: direct current (缩写 DC) clectric current flowing in one direction 直流电
ad: anno domini (latin) means in the year of our lord of the christian era 公元
bc: before christ 公元前
PS:请认真读题
参考资料：OXFORD ADVANCED LEARNER'S ENGLISH CHINESE DICTIONARY
公元前
公元后
哈哈 口语中AC还可以指代Air Conditioner空调
AC是缩写, 全名是 Alternating Current(交流电).
An electric current that reverses direction in a circuit at regular intervals.
DC也是缩写, 全名是 Direct Current (直流电).
An electrical current that travels in one direction and used within the computer's electronic circuits.
AC也可以解释为, Ante Christum (＝ before Christ)(拉丁语)公元前
其他AC和DC的用处也有,比如AC/DC是一个乐团的名字,A/C也可以用与空调的缩写(Air Conditioning),当然..还有AC Millan...意大利足球俱乐部...
如果是用于产品的话一般都出现于电子产品上噶~~AC,DC电源