CHAPTER 19

Circuits

IN THIS CHAPTER
Summary: Electric charge flowing through a wire is called current. An electrical circuit is built to control current. In this chapter, you will
learn how to predict the effects of current flow.

Key Ideas
The current in series resistors is the same through each, whereas the voltage across series resistors
adds to the total voltage.
The voltage across parallel resistors is the same across each, whereas the current through parallel
resistors adds to the total current.
The brightness of a light bulb depends on the power dissipated by the bulb.
A capacitor blocks current once it has been connected for a while.
Physics C students need to know that the time constant of an RC circuit is RC .

Relevant Equations

Definition of current:

Resistance of a wire in terms of its properties:

Ohm’s law:

V = IR

Power in a circuit:

P = IV