Lesson 2 – V: Voyage into Volt: How Do Electrical Circuits Work Safely? 

Electricity Needs a Path 

Electricity does not move through a random pile of parts. Current flows only when the parts create a complete path, known as a closed circuit.  A closed circuit is a complete pathway that allows electric current to move from an energy source, through electrical components, and back to the source. In a simple battery-powered circuit, the source is the battery, conducting wires provide the path, a switch can control the path, and a load, such as a light bulb, LED, buzzer, or motor, uses electrical energy to produce light, sound, motion, or heat. A closed circuit has an unbroken loop from one battery terminal, through the wires and load, and back to the other battery terminal, so current can flow and the load can operate. An open circuit has a gap somewhere in that loop, such as an open switch, a disconnected wire, or a loose connection, so current cannot complete the path and the load stays off. 

A short circuit is different: the circuit may be complete, but current takes an unintended, very low-resistance route that bypasses the intended load or connects the source terminals too directly. For example, placing a wire directly between the positive and negative terminals of a battery creates a shortcut rather than sending current through an LED and its resistor. This can cause excessive current, heating, battery drain, or damage, so you should explore short circuits only in a simulation, not with real batteries or wires.