This module was developed as remedial material for physics students who have difficulty understanding concepts of circuits and calculating resistances, and voltage drops and currents. Lists of prerequisite skills and instructional objectives are followed by a pretest (with answers). Students are directed to the subject matter in the module based on the number of and what questions were missed in the pretest. Objectives include defining the nature and operation of a battery; defining voltage, current, resistance, and direct current; calculating resistance; calculating current in a direct circuit; and calculating voltage output of a battery in a circuit. Prerequisite skills include understanding that an electron is a particle of negative charge orbiting around the nucleus of an atom, understanding that electrons are able to be removed from the atom and transferred to another atom (this movement of the electron's charge being called a current), and having the mathematical skills to complete correctly such problems as are found in the pretest. The module concludes with a 10-item posttest, indicating completion of the module if 2 or less items are incorrect and suggesting a review of topics missed if 4 or more questions are answered wrong. (Author/JN)