1A mains electricity supply.
2A device or arrangement for converting a supply from the mains into a low-voltage direct-current form suitable for a valve or transistor.
Late 19th century; earliest use found in Science.
英汉双解词典包含464360条英汉词条，基本涵盖了全部常用单词的翻译及用法，是英语学习的有利工具。