Electric circuits — Engineering, 11–13
A circuit gives electric charge a complete path through components. Understanding the path explains why a lamp lights, why a switch works and why adding branches can change what happens.
A circuit is a complete path
Electricity can make a component work only when there is a complete conducting path from one side of the power source and back to the other. A battery, wires, switch and lamp form a circuit. Opening the switch creates a gap, so the lamp goes out.
Why engineers draw circuits
Before building a device, engineers need to predict where electricity will go and what each part will do. Circuit diagrams make connections clear without showing every physical detail. This solves a practical problem: a design can be checked, changed and shared before components are assembled.
Making a lamp light
Connect the battery’s positive terminal to one lamp contact with a wire. Connect the lamp’s other contact to the switch, then connect the switch back to the battery’s negative terminal. Close the switch: the path is complete and the lamp lights. Open it: the gap breaks the path and the lamp goes dark.
A circuit is not just wires touching
It is reasonable to think that touching wires should be enough, because metal objects conduct electricity. But the path must include the right terminals of the components and return to the source. A loose connection, an insulating covering or a wrong terminal can leave a gap even when everything looks close.
Circuits all around you
A bicycle light, doorbell, torch and game controller all use circuits. Their switches open or close paths, while batteries or mains supplies provide energy. More complex devices contain many paths and control parts, but the basic question stays the same: is there a safe route for electricity to do its job?
Keep exploring
Other languages
Loading MyLeoNes™…