Ch.14 ELECTRICAL ENGINEERING

RELATES BOTH ELECTRICITY AND ELECTRONICS

Conventional Current vs Electron Flow

ELECTRONIC VS ELECTRICAL ELECTRONIC MADE WITH SEMICONDUCTOR MATERIAL USUALLY SILICON EXAMPLES-DIODES, TRANSISTORS, RECTIFIERS, SUPRESSORS ELECTRICAL MADE WITH CONDUCTOR MATERIAL METALS AND ALLOYS EXAMPLES- WIRES, SWITCHES, FUSES

ALLOY A homogeneous mixture made by fusing two or more metals, or a metal and a nonmetal To obtain desirable qualities such as hardness, lightness, and strength Brass is a mixture of zinc and copper

ELECTRICAL CIRCUITS ELECTRON FLOW OCCURS FROM THE NEGATIVE TERMINAL (where there is an excess of negative electrons) TO THE POSITIVE TERMINAL (where there is a lack of electrons) CONVENTIONAL CURRENT FLOWS FROM POSITIVE TERMINAL TO NEGATIVE TERMINAL

14.1 Electrical Functions Is the role that a component plays in the control of electric current. Circuit diagrams show where the components are placed. Ex of components: power supply Switch Diode Light bulb etc

SYMBOLS FOR CIRCUIT DIAGRAMS BATTERY AC POWER SUPPLY

DIODE LED

TRANSISTOR SWITCH

RESISTOR OTHER SYMBOLS PAGE 460 OBSERVATORY

14.2 DC vs AC Current DIRECT CURRENT: UNIDIRECTIONAL FLOW OF ELECTRIC CHARGE ELECTRONS MOVE CONTINUOUSLY IN THE SAME DIRECTION

ALTERNATING CURRENT: Alternating flow in which the electrons move back and forth in a regular pattern. The vibrating motion of electrons allow current to flow.

POWER SUPPLY PROVIDES THE ENERGY THAT CAUSES THE CURRENT TO FLOW THROUGH THE CIRCUIT

ADVANTAGES AND DISADVANTAGES OF A BATTERY A battery is a device that transforms the energy from a chemical reaction into electrical energy. Advantages: Products that run on a battery are portable Disadvantage: Batteries have to eventually be replaced. Plus, the chemicals inside a battery are an environmental hazard and leak heavy metals and acids into our environment. Examples: MP3 players, watches, remote controls

ADVANTAGES AND DISADVANTAGES OF AN OUTLET An outlet is designed to have metal prongs in constant contact with an electrical network Advantages: Stable and long lasting power supply. It also creates very little greenhouse gases (as Hydro Quebec uses water to produce electricity) Disadvantage: Appliances are needed to be in constant contact with the outlet and has minimal movement. Examples: TV, Fridge, Computers

ADVANTAGES AND DISADVANTAGES OF A PHOTOVOLTAIC CELL A photo cell (solar cell, or solar panel) generates an electrical current when exposed to light (sun). Advantages: They can create electrical power to an electric grid, and they can create power on portable devices. They do not produce greenhouse gas emissions and have a life span of 20 – 30 years Disadvantage: Is dependable on the sun. They are also very expensive to install.

14.3 Power Supplies: AdvantagesDisadvantages Battery (chemical energy  electrical energy) PortableHave to be replaced! Environmental hazard! Electrical OutletStable source of power Close proximity Photovoltaic Cell (sun energy  electrical energy) PortableDepends on weather! Expensive to install!