Alternating and Direct Currents

[highlight] [b]Voltage[/b] - the difference in charge between two points. [b]Current (Amps)[/b] - the rate at which charge is flowing. (It is the amount of [b]coulombs[/b] (6.24*10^18) passing a point in one second) [b]Resistance[/b] - a material's tendency to resist the flow of charge (current). [/highlight] [h3]Alternating Current - AC[/h3] Alternating Currents are currents which periodically change in direction. The direction of the Current is changes between around 50 or 60 times a second, this is called the frequence (Hz). It alternates between a negative peak and a positive peak so looks something like this: [img src='https://res.cloudinary.com/deylrqt2d/image/upload/v1485648131/oscillator_graph.png'] Due to the fact that the charge changes, the Voltage changes as well, so the voltage is plotted on the [b]y[/b] axis of the graph, rather than the direction - and time is on the [b]x[/b] axis to represent the change. The alternation of the current is measured using an instrument named and [b]oscilloscope[/b]. [h3]Direct Current - DC[/h3] Direct Currents are much simpler, it is simply the flow of electrons from one terminal to another with no oscillations. [img src='https://res.cloudinary.com/deylrqt2d/image/upload/v1485648415/direct_current_graph.png'] The above is an oscilloscope graph's view of a DC current. According to classical conventions, the electrons went from the [b]negative terminal[/b] of a battery/cell, to the [b]positive[/b] one. However in reality the current flows from the [b]positive terminal[/b] of a battery/cell, to the [b]negative[/b] one. The classical convention is called [b]Conventional Current Flow[/b]. The real one is called the [b]Real Current Flow[/b].