200 likes | 210 Views
Learn about the basics of electricity, units (kWh), electrical power, meters, main circuits, and simple calculations. Explore the connection of live, neutral, and earth wires, plugs, fuses, and examples. Discover how to read an electricity bill and the role of suppliers in Hong Kong.
E N D
Target audience: F.3 Basic knowledge: Unit of electricity Simple Calculation about Electricity
Electrical Power • Unit of electricity • Kilowatt-hour meter • Main Circuit Content
Power = Energy change / time unit of power: Watt (W) unit of energy: Joule (J) unit of time: second (s) 1W = 1Js-1 Electrical Power
- The energy consumed in household appliances is measured in kilowatt-hours (kWh) Unit of Electricity - One kilowatt-hour is the amount of energy that is used by a 1000 W appliance in one hour.
The total cost of electricity consumption in June 0.12 0.28 0.4 12 0.084 0.196 0.28 8.4 12.8 384 8.96 268.8
Chan Tai Man 13 Nathan Road Kowloon 85467-253-07 Chan Tai Man 13 Nathan Road Kowloon 59 共 日用電量 28-04-98 01-03-98 28-04-98 由 至 06-05-98 Electricity Bill
Kilowatt-hour meter When the mains cable enters the home, it is connected through a fuse to a kilowatt-hour meter.
Main Circuit Live wire (火線) This carries the alternating current to the appliance. Neutral wire (中線) This carries the alternating current to the appliance. Earth wire (地線) It connects the metal body of the appliance to the earth. If a live wire becomes loose and touches the metal body, a large current flows to earth. The person does not get an electric shock.
Standard Socket and Plug Wire Symbol Colour Live L brown Neutral N blue Earth E green and yellow
E L N Wiring in a 3-pin plug The live wire is joined to the live pin through a cartridge fuse. The other wires are screwed directly to their corresponding pins.
X Y FUSE Z Appliances with an earth and a fuse X is Y is Z is Neutral Live Earth
Through a faulty kettle without fusing and earthing BOMB BOMB BOMB
Earth The ring circuit Neutral Live
Neutral Live Circuit in our home
Neutral Live Example:
Neutral Live Example:
Two Electrical Suppliers in Hong Kong: China Light & Power Co. Ltd. http://www.chinalightandpower.com.hk Hong Kong Electric Holdings Ltd. http://www.hec.com.hk