This resource is one of a series of free online textbooks on electricity and circuits, appropriate for both traditional classroom instruction and independent study. It is part of the Open Book Project, and is an ongoing effort managed by author Tony Kuphaldt. This volume includes chapters on basic concepts in electricity, Ohm’s Law, series and parallel circuits, Kirchhoff’s circuit laws, batteries and capacitors, metering circuits, and inductance. Each chapter is supplemented with related diagrams, photos, and detailed explanations of mathematical formulas. The author uses a less formal writing style intended to engage a broad variety of learners regardless of prior knowledge. SEE RELATED MATERIALS: for a link to additional free textbooks offered for higher-level courses in electricity and electronics.