Electrical Engineering Electrical Engineering Covers two main areas

Electrical Engineering

Electrical Engineering �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)

Symbols for circuit components

Direct current & Alternating current � 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

Electrical Function �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

Types of power supplies � 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, insulation & protection � 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

Protection: Cut current flow in the even of a power surge � Fuses � Breakers �A �A filament melts/breaks if current exceeds a certain level strip becomes hot and bends if current exceeds a certain level. A switch is thrown to restore circuit operation

Open/closed circuit � Closed circuit: electric current lows in a loop � Open circuit: electric current cannot flow in a loop

In class work �P. 479 �#1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14

Transformation of energy �The transformation of energy is the electrical function performed by any component that can convert electrical energy into another form of energy

Forms of energy �Chemical �Thermal �Mechanical �Radiation

Examples of electrical components used to transform electrical energy � Incandescent light bulbs (luminous energy) � Heating elements (thermal energy) � Piezoelectric crystals (mechanical energy) � Electromagnets (magnetic energy)