How do light switches work?



How do light switches work?

In: Technology

Just think of an actual fence and gate. Imagine the fence is the electrical wire and the gate is the switch. When the gate is open, the circuit is broken, the switch is off, no electricity can pass through. When you close the gate by turning the switch on, you complete the circuit and let the electricity flow through to the rest of the fence/wire

An electrical item works when the circuit is completed so electricity can flow into and out of the item. If you think of the wire like a train track with the electricity like a train moving along the train track, the switch is like a switch on the tracks stopping or allowing flow along the track.

You flip the switch to the upwards position and it turns on. On the other end, if you want to turn it off, you flip it downwards. It’s easy

Electricity the way we use it requires a closed loop of metal to flow. When the lights are off, it means the loop is broken somewhere. All you have to do to fix the loop is to touch the broken pieces of metal together and the flow will be restored. You can connect and disconnect the loop as many times as you like to turn the circuit off and on. A light switch is simply a standardized, safe way to do this connecting and disconnecting.

An important feature of a light switch is its “clicky”-ness. When you disconnect a circuit that has power flowing, the power wants to keep flowing. It’s not so simple as “oh, it’s not touching metal anymore, time to stop”. In the microseconds of time where you’ve pulled the pieces of metal apart and there’s a tiny air gap between them, the current can jump straight through the air, just light lightning but on a smaller scale. They call this “arcing” (ark-ing). Arcing is bad because it can melt the metal contacts and ruin them. The heat from arcing can also burn nearby materials and start fires. So you want to minimize this effect as much as you can. More sophisticated equipment can do it by filling the switch with special fluids that resist arcing better than air, but the more economical solution used by household switches is to snap the connection apart as fast and violently as possible. This violent snapping causes the clicking sound that all light switches should have. If you ever encounter a light switch without this, it’s probably worn and needs replacement.