An explanation of the difference between direct and alternating current. The clip includes a short historical outline of the work of Thomas Edison and Nikola Tesla. This is followed by an ...

Alternating current (a.c.) is an oscillation of electrons or 'back and forward' movement. One full cycle of alternating current is shown in the diagram below: ...

Getting that single directional flow was critical for radio sets which needed to turn alternating current ... control the flow of a second, more powerful current, through the tube.