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).
A watt is a unit of power that measures the rate of energy transfer or usage. A kilowatt is equal to 1,000 watts. A kilowatt hour is the amount of electricity used. To calculate the amount an appliance uses in kilowatt hours, take its wattage, multiply it by the number of hours you use it, and divide by 1,000.If you take a 100-watt light bulb and use it for 540 hours, the light bulb will use 54 kWh of electricity.f you look at your power bill, you will see your monthly kilowatt hour usage. This is how much electricity you used for that month and were charged for. Normally your power company will bill you based on a rate per kWh. Sometimes this rate varies depending on the time of day or your usage.