Chapter 4: Energy
The Laws
| Name | Equation or Description |
| Ohm's Law | V (volts) = I (amperes) R (ohms) |
| Watt's Law | P (watts) = V (volts) I (amperes) |
| Energy Conservation | Energy can neither be created nor destroyed |
Some manipulations
P = V I =(I R) I = I2R
P = V I = V (V/R) = V2/R
etc.
Some Definitions
Wattmeter
Measures instantaneous power
Watt-Hour Meter
Measures amount of power used in a given time
% Efficiency
Power out/Power in x 100
Energy Efficiency Rating
Listed on appliances, calculated as above - %
efficiency