photo.jpg

## Moving Charges - Electric Current **Define electric current.** The amount of charge that passes through a wire in a given period of time is termed as electric current. **Electric Circuit** The pathway travelled by electrical energy is called an electric circuit. As electrically charged particle...

## Moving Charges - Electric Current **Define electric current.** The amount of charge that passes through a wire in a given period of time is termed as electric current. **Electric Circuit** The pathway travelled by electrical energy is called an electric circuit. As electrically charged particles move around an electric circuit, they carry electrical energy from the energy source, such as a battery, to the device that uses the energy, such as a torch, through a conducting material, such as a piece of copper wire or some other metal. Devices have 'gaps' called switches to control the flow of electricity in a circuit. A chemical reaction inside the battery push electrons out of the negative (-) terminal and round to the positive (+) terminal. As the electrons pass through the thin wire, or filament, inside the bulb they make it heat up, so that it glows as shown in figure. **Do you know?** The unit for the current is the ampere, named for André Marie Ampère, an early investigator of electricity. The name of the unit is often shortened to A. An ammeter is an instrument which is used to measure electric current. The larger the current, the greater the flow of electrons and the greater the number of amperes. **Circuit diagrams** Circuits are represented using circuit diagrams. Each component of a circuit is represented by a symbol. Connecting wires are usually shown as straight lines, and when they meet at junctions they are often (but not always) joined at right angles. The longer line on the battery represents the positive terminal and the shorter line represents the negative terminal. These terminals are where the wires are connected. | Component | Symbol | Component | Symbol | |---|---|---|---| | Wire | - | Closed switch | | | Cell | | Resistor | | Electricity can make your hair stand up when rubbed by a balloon. This kind of electricity is called static electricity.