Electrical Engineering Technological World Chapter 14

Electronics vs. Electricity Electrical Appliances (ex: toasters) and Electronic Devices (ex: cell phones) depend on electrical currents. Electronics Electricity Made of SEMICONDUCTORS (usually silicon) Made of CONDUCTORS- metals and alloys (copper) MINIATURE, LOW-INTENSITY currents POWERFUL currents Conduction is finely controlled  they can process information Conduction is not as finely controlled

Electrical Circuits Conventional Current Flow: From + to – terminal on the power supply (battery) Electron flow: FROM – TO + terminal on the power supply

Direct Electric Currents Electrical currents are caused by the movement of electrons. DC happens when electrons move in 1 direction within a circuit. Anything requiring a battery works on a direct current. Electronics use direct currents as well.

Alternating Electric Currents Electrons within the circuit move in a back and forth direction. The electricity we get from Hydro Quebec is an example of alternating electric currents. http://www.youtube.com/watch?v=BcIDRet787k http://www.youtube.com/watch?v=HqMqdFNWX4s

Why use AC instead of DC? AC is much less expensive than DC! Less space is required More reliable