A positive connection is one in which a change (increase or decrease) in some variable results in the same type of change (increase or decrease)in a second variable. The positive connection in the figure below for a cooling coffee cup implies that the hotter the coffee is the faster it cools.
The power consumption of small devices is usually measured in Watts, and the power consumption of larger devices is measured in kilowatts (kW), or 1,000 Watts. Electricity generation capacity is often measured in multiples of kilowatts, such as megawatts (MW) and gigawatts (GW).
The most common unit of measurement on the electricity meter is the kilowatt hour [ kWh ], which is equal to the amount of energy used by a load of one kilowatt over a period of one hour, or 3,600,000 joules.nother type of smart meter uses nonintrusive load monitoring to automatically determine the number and type of appliances in a residence, how much energy each uses and when. This meter is used by electric utilities to do surveys of energy use.