This document defines and describes different types of electrical circuits. It discusses simple closed circuits consisting of a power source, switch, and resistor or capacitor. Circuits are classified as simple/closed, open, or short. Simple circuits allow current to flow in a complete loop from the power source to a consuming device and back. Open circuits have a broken connection, while short circuits allow current to flow directly from the power source without passing through a device. Kirchhoff's laws, Ohm's law, and the differences between series and parallel circuits are also summarized.