This publication is the second in a series of three texts for a diesel mechanics curriculum. Its purpose is to teach the concepts related to electricity and circuitry in a diesel trade. The text contains nine units. Each instructional unit includes some or all of these basic components: unit and specific (performance) objectives, suggested activities for teachers and students, information sheets, transparency masters, assignment sheets, answers to assignment sheets, job sheets, pencil-paper and performance tests, and answers to tests. Introductory materials include description of unit components, instructional/task analysis (psychomotor and cognitive skills to be learned), listing of needed tools and equipment, and reference list. Unit titles are Introduction to Electrical Systems, Electrical Circuits, Electrical Indicator Circuits, Storage Batteries, Starting Circuits, Ignition Circuits, Generator Charging Circuits, Alternator Charging Circuits, and Emergency Shut-Down Circuits. (YLB)