Circuits are a key component of the game and are necessary for most automated systems.

Circuits operate by sending signals along networks of electrical cables. Cables can transmit both electrical power and data at the same time. Data networks should be attached to the data port of relevant machines. The cable networks work as a bus, with all objects on a network visible to each other. Objects with two data outputs, most notable of which is the Area Power Controller, generally form two discrete networks.

Circuits act on a half-second tick, which can be important for timer circuits and advanced applications.