This course introduces alternating current (AC) theory and expands into the principles and operation of DC motors and generators used in aircraft systems. It covers waveform characteristics, sinusoidal behavior, and the effects of resistance, capacitance, and inductance on circuit performance. Students examine impedance, phase relationships, and power factor, as well as power calculations in AC circuits. The course also addresses the construction, operation, and performance of electrical machines. Practical components are integrated through AC measurements, circuit analysis, and testing of motor- generator systems, ensuring a strong alignment with EASA Module 3 standards.