Although many practical applications and devices are based on the principles of static electricity, electricity did not become an integral part of our daily lives until scientists learned to control the movement of electric charge, known as current. Electric currents power our lights, radios, television sets, air conditioners, and refrigerators. Currents also are used in automobile engines, travel through miniature components that make up the chips of computers, and perform a number of invaluable tasks.

This unit explores the properties of batteries and how they cause current and energy transfer in a circuit. This analysis includes the concepts of current, potential difference (“voltage”), resistance, electromotive force, dc circuits, and electrical energy.