Likestrøm

Likestrøm is a term used in electrical engineering to describe a current that flows in one direction only. Unlike alternating current (AC), which periodically reverses its direction, direct current (DC) maintains a constant polarity. This unidirectional flow is a fundamental concept in electricity and is generated by various sources, including batteries, solar cells, and DC generators.

The behavior of DC is simpler to analyze and control compared to AC. In DC circuits, Ohm's Law, which relates voltage, current, and resistance, applies directly. Components like resistors, capacitors, and inductors behave predictably when subjected to DC. Capacitors will charge up to a certain voltage and then block further current flow, while inductors will oppose changes in current but eventually allow steady DC to pass.

Many electronic devices, such as smartphones, laptops, and LED lights, rely on DC power. While these devices are often plugged into AC wall outlets, they contain internal power supplies that convert the AC into the DC required for their operation. This conversion process, known as rectification and regulation, is crucial for the functionality of modern electronics. The transmission of DC power over long distances has also seen renewed interest due to advancements in high-voltage direct current (HVDC) technology, which can offer advantages in efficiency and stability for certain applications.