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Covers two main areas: - Electricity - Electronics All appliances and electrical devices depend on electrical circuits Electrical component are made with a particular type of material: - Semiconductor (silicon) - Conductors (metals & alloys) Direct current (DC): is an electric current in which the electrons are continuously moving in the same direction. Alternating current (AC): is an electrical current in which the electrons move back and forth in a regular pattern Is the role that a component plays in the control or transformation of electric current. Power supply: is the electrical function preformed by any component that can generate or provide an electric current in a circuit Battery: Transforms chemical energy into electrical energy Advantages: portable, many appliances run on batteries Disadvantages: batteries must be replaced, contaminate the environment around the landfill by leaking heavy metals Electrical outlet: contains contacts and is permanently connected to an electrical network Advantages: stable and long lasting power supply Disadvantages: hydroelectric dams cause flooding of vast areas of land. Appliances cannot be moved far from the wall outlet Photovoltaic cell: (solar cell) electronic device that generates an electrical current when exposed to light. Advantages: portable, do not produce green house gases, have a lifespan of 20 to 30 years. Disadvantages: Depends on sunny conditions. Much more expensive to install than other sources of power. Conduction: When a component can transmit electric current from one part of a circuit to another Examples of conductors: copper, gold, etc... Insulation : When a component prevents an electric current from flowing. Examples of insulators: ceramic, rubber, plastic Fuses A filament melts/breaks if current exceeds a certain level Breakers A strip becomes hot and bends if current exceeds a certain level. A switch is thrown to restore circuit operation Closed circuit: electric current flows in a loop Open circuit: electric current cannot flow in a loop P. 479 #1 to 8, 10, 11, 13, 15 The transformation of energy is the electrical function performed by any component that can convert electrical energy into another form of energy Chemical Thermal Mechanical Radiation Incandescent light bulbs (luminous energy) Heating elements (thermal energy) Piezoelectric crystals (mechanical energy) Electromagnets (magnetic energy)