A straight line represents an electrical wire as conductor of electrical current, while two intersecting lines with a point connecting them represent a connected crossing. Intersecting lines with a semicircle connecting them indicate that the two wires are not connected.
Other common electrical diagram symbols include the solder bridge symbol, which shows an electrical wire being punctuated by two halves of a semicircle; this indicates that the connection must be soldered. The DIP switch symbol looks like several parallel lines emanating from a rectangle that has an even number of smaller empty rectangles inside.
A line intersected by two short perpendicular lines and connected by a second parallel line indicate a connection that requires jumper pins to be closed. The resistor symbol either looks like a saw wave or like a small clear rectangle intersecting a line. The saw wave resistor symbol refers to the IEEE diagram model, while the rectangular symbol refers to the IEC diagram model.
Capacitor symbols interrupt electrical lines either with two parallel lines drawn perpendicular to the existing line, or with a single perpendicular line and a second concave line. Additional plus or minus-sign symbols indicate whether the capacitor is polarized.
Some electrical measurement devices are represented by diagram symbols that use lettering, such as the voltmeter and wattmeter. Voltmeters are indicated with an encircled V, while wattmeters are indicated with an encircled W.