Circuits can consist of a variety of circuit components. Each component has its own properties and functions.

In a circuit diagram, specific symbols, known as circuit symbols, are used to represent these components.

Electric current is a flow of electrical charge. Electrical charge is measured in Coulombs (C) and current is measured in amperes (A). The current can be thought of as the rate of flow of charge around the circuit. You can measure current using an ammeter. You can calculate the charge that has flown around a circuit in a certain time (s) using the following equation:

Formula

• $Q$= charge flow in coulombs (C)
• $I$= current in amps (A)
• $t$= time in seconds (s)

Remember that current will only flow through a circuit when it makes a complete loop.