BellringerTwo AA batteries in series will provide a voltage of how many

volts?

Electric PowerNotes

Electric Power

All electrical appliances change electrical energy into another form of energy. For example, a hair dryer changes electrical energy into thermal energy.

Electric Power

Power is the rate at which energy is changed from one form to another. The unit of power is the watt, which is abbreviated as W. Each electrical device has a power rating.

Electric Power

The power of an electrical device depends on the voltage and the current. The equation to calculate power is:

•Power = Voltage X Current

•where

•Watts(W) = Volts(V) X Amperes(A)

Electric Power

You can use the symbols P for power, V for voltage, and I for current. Using these symbols, the power equations can be written this way:

•P=VI

Electric Power

PV I

P = Power measured in Watts

V = Voltage measured in Volts

I = Current measured in Amps

Electric Power

A clock radio uses the standard voltage of 120V. The clock radio has 0.1A of current in it. What is the power rating of the clock radio?

Electric Power

A hair dryer has a power rating of 1200W and uses a standard voltage of 120V. What is the current through the hair dryer?

Paying for Electrical Energy

Different appliances change electrical energy into other forms of energy at different rates. The more you use an appliance, the more energy it consumes.

Paying for Electrical Energy

The equation to calculate the amount of energy an appliance consumes is:

•Energy = Power X Time

The unit of electrical energy is the kilowatt-hour, which is abbreviated as kWh. One kilowatt is equal to 1000 watts.

Therefore:

•Kilowatt-hours = Kilowatts X Hours

Paying for Electrical Energy

Ten 100W light bulbs turned on for one hour use 1,000 watt-hours (or 1 kilowatt-hour) of energy.

•E = PT

•E = 10(100W) X 1 Hour

Paying for Electrical Energy

EP T

E = Energy measured in

kilowatt-hours

P = Power measured in Watts

T = Time measured in Hours

Paying for Electrical Energy

The amount of electrical energy used in your home is measured by a meter. As more lights and appliances are turned on, you can observe a dial on the meter turning more rapidly.

In general, you pay a few cents for every kWh of electrical energy you consume.

240V Charger 24kWh Battery Pack

Charges in 8 HoursWhat is the current?

Nissan Leaf Charging Current

Nissan Leaf Charging

Based on the derived information, how much resistance does the Leaf system apply to the current?

Nissan Leaf Charging Resistance

R = V/I

R = 240V / 12.5A

R = 19.2Ω