Some common electrical symbols are a line, which denotes an electrical wire, two lines perpendicular to each other with a dot at the intersection, which signifies two connected wires, and two perpendicular lines without a dot, which means two wires that are not connected. These symbols represent electrical and electronic components in a schematic diagram. If the symbols connect to form a loop, it is a closed circuit, and if the symbols do not, it is an open circuit.
Variations on the same symbol are used to represent the different types of resistors. A zigzag line is used to symbolize a simple resistor. The same symbol with an arrow overlaid diagonally on it means it is a variable resistor. A zigzag line with a small arrow pointing perpendicularly toward it stands for a potentiometer resistor.
Other common symbols for electrical schematics include earth ground, which is a vertical line with three horizontal lines under it in the shape of a downward facing arrowhead, an ideal source, represented by a circle with a plus sign on one side and a minus sign on the other, a capacitor, which is drawn as two small lines perpendicular to the circuit with a gap between them, and a battery, which is illustrated by three pairs of small and large lines perpendicular to the circuit with gaps between each of them.