Save guides, add subjects and pick up where you left off with your BBC account. A direct current flows in only one direction. On a voltage-time graph this would appear as a straight horizontal ...

Save guides, add subjects and pick up where you left off with your BBC account. A direct current flows in one direction only. On a voltage-time graph this would appear as a straight horizontal ...

However, once upon a time, direct current was the standard, and it wasn’t until the conclusion of a decade-long feud between Nikola Tesla and Thomas Edison that the world settled on AC.