D.C. (Direct Current) is a type of electrical current that flows in a single direction. Unlike alternating current (AC), which changes direction periodically, D.C. maintains a constant voltage and current. This makes it ideal for powering devices like batteries, electronics, and solar panels, where a stable power supply is essential. D.C. is commonly used in various applications, including computers, LED lighting, and electric vehicles. Its straightforward nature allows for easier storage and conversion, making it a fundamental component in modern technology. Understanding D.C. is crucial for anyone working with electrical systems or devices.