Cracking the SAT Physics Subject Test

CIRCUIT ANALYSIS

We will now develop a way of specifying the current, voltage, and power
associated with each element in a circuit. Our circuits will contain three basic
elements: batteries, resistors, and connecting wires. As we’ve seen, the resistance
of an ordinary metal wire is negligible; resistance is provided by devices that
control the current: resistors.

All the resistance of the system is concentrated in resistors, which are

symbolized in a circuit diagram by this symbol

Batteries are denoted by the symbol

where the longer line represents the positive (higher potential) terminal,

and the shorter line is the negative (lower potential) terminal.

Here’s a simple circuit diagram.