http://www.ck12.orgCHAPTER
18 Current Electricity
Chapter Outline
18.1 Electric Current and Circuits
18.2 RESISTANCE ANDOHM’SLAW
18.3 ENERGYTRANSFER INELECTRICCIRCUITS
18.4 CONTROLLINGCURRENT INELECTRICCIRCUITS
18.5 REFERENCES
One of the most important characteristics of electrical energy is its ability to be transferred over long distances. High-
voltage electric power distribution lines can be found scattered everywhere throughout the United States. They are a
common reminder of our dependence on electricity. A great deal of engineering has gone into making those power
distribution lines reliable and efficient. The enormous amount of potential energy harnessed by a power station like
the Grand Coulee Dam is of no value to a factory ten miles away unless that energy can be transferred efficiently
from the dam to the factory. This chapter will explore how electric currents function and how we control them.