Tasajännitteessä

Tasajännitteessä is a Finnish term that translates to "in direct current" or "DC" in English. It refers to an electrical system where the electric charge flows in one constant direction. This is in contrast to alternating current (AC), where the direction of charge flow periodically reverses.

Direct current is commonly produced by batteries, solar cells, and DC generators. Many electronic devices, such as smartphones, laptops, and other portable electronics, operate on direct current. Inside these devices, AC power from the wall outlet is typically converted to DC using a power adapter or internal circuitry.

The historical development of electricity distribution saw a debate between direct current and alternating current. Thomas Edison was a proponent of DC, while Nikola Tesla and George Westinghouse championed AC. Ultimately, AC proved more efficient for long-distance power transmission due to its ability to be easily stepped up or down in voltage using transformers. However, DC remains essential for many specific applications, particularly in electronics and for certain industrial processes. The voltage in a DC circuit is constant over time, unlike AC where the voltage varies sinusoidally.