Measuring Electricity

The basic unit of electricity is the watt, named after the Scottish inventor James Watt (1736-1819), who perfected the steam engine and the rotary engine.  

Watt also coined the term “horsepower” as a measure of how much work an engine was performing. The watt, on the other hand, is the unit of power in the metric system.  

A watt is the amount of power that is delivered when a current of one ampere flows through
an electric circuit and a voltage of one volt exists across it. It is quite a small unit of power.  


Typically, household lighting draws between 20 and 100 watts. Household appliances like hair dryers, toasters, heaters and kettles draw 500 to 1500 watts of power.  

A household electrical bill is measured in kilowatt hours. A kilowatt is 1,000 watts. If you operated
a 1,000 watt heater for an hour you would have used a kilowatt hour of electricity.  

Power station output is measured in millions of watts or megawatts. A 200 megawatt unit
generates enough electricity to supply a city the size of Bendigo at peak times or a city
the size of Geelong at quieter times.