ocr: Circuit boards, part 1. - 0 An llustration will be given on the next page of how circuit boards are used to plug different devices into the computer's bus. But, first, it needs to. be shoun that on the next page the llustration of the computer is rotated as indicated here. Bus Random Access Memory Central Processing Unit Page 39 Copyright C, 1991, Chester Langin, 532 W. 3rd St., Centralia, IL 62801, All rights reserved.