Silicon Valley star Thomas Middleditch is engaged to his girlfriend Mollie Gates, Us Weekly can exclusively confirm. PHOTOS: Celebrity weddings 2015.
Why, Alternating Current and Direct Current, of course! Both AC and DC describe types of current flow in a circuit. In direct current (DC), the electric charge (current) only flows in one direction. Electric charge in alternating current (AC), on the other hand, changes direction periodically. The voltage in AC circuits also periodically reverses because the current changes direction.
In alternating current, or AC, the electron flow reverses 120 times each second (in the USA) or 100 times each second (Europe). This is the way electricity is delivered to homes in nearly all of the developed world.