It would be tough to get too far in electronics without running into some form of Alternating Current (AC).
So what is Alternating Current?
Basically, what is "alternating" in alternating current is the polarity of the voltage source, which causes the current to flow in one direction, and then reverse, and flow in the opposite direction.
That's why the main difference you will see between DC and AC circuit diagrams, is that in the AC circuit diagrams, there will be no indication of polarity, or + and - signs.
This is because the polarity of the voltage source, and the direction and magnitude of the flow of current is continually changing or alternating.
The most common form of AC is the Sine Wave, which is the one we will be dealing with the most.
The changing nature of this wave, or current, will present some challenges, but nothing we can't handle!
In the next lesson, we'll look at all of the parameters we will need to know to understand AC.