Circuits intro

• An electrical circuit is a closed loop that contains a power source such as a cell and something for the electrons to flow through, represented by a wire.
• Potential difference, denoted by v, is the force driving the flow of electrons and is provided by the cell or battery.
• Current, denoted by i, is a measure of the flow of electrons around the circuit and is measured in amperes, often referred to as amps, and denoted with the letter a.
• Resistance, denoted by r, is everything that resists or opposes the flow of electrons and is measured in ohms.
• In an electrical circuit, current always flows from the positive terminal to the negative terminal.
• The positive terminal in a cell or battery is always longer than the negative terminal.