An electrical switch schematic works by using visual representations to depict the proper configuration of electrical components such as transistors, inductors and resistors in addition to the conductive wires used to transport current between the components. Four-way switches are typically represented by schematics either beginning with a power source sequentially directed through the switch-controlled device into a three-way switch, a four-way switch and another three-way switch, or with a power source directed into a three-way switch.
Four-way switch wiring is a particularly useful method for controlling a light fixture from three or more locations. Four-way switches can only be successful when installed between two three-way switches. Additional switches can be added to the schematic by simply adding a four-way switch next to an already existing four-way switch.
WFU.edu contains an informative animated schematic of the workings of a four-way switch. The website also provides non-animated schematics of the possible light configurations and power source options for four-way switches. How-to-Wire-It.com also has an in-depth explanation of the workings, functions and differences of four-way switches. How to Wire It, as well as many other electrical wiring education websites, stress the fact that three-way switches must be understood before constructing a four-way switch.