Power supplies are energy conversion devices and are a key component in a world where Earth's resources and environment are becoming problematic. This book, aimed at aspiring power supply engineers, explains everything from building power supplies to applying circuits, even for elementary and junior high school students. Publisher: Nikkan Kogyo Shimbun Release Date: 1998/11/1 Condition: There are no noticeable scratches. Also, the text is clean with no writing or highlighting. Overall, it is in good condition. Although we have checked it thoroughly, please understand that as a used item, there may be some overlooked scratches, stains, or highlighting.