Relays> Sometimes, you need a <#5968,15><!switch> that can be triggered automatically. For instance, just like cars, trains follow red lights (stop) and green lights (go). But there’s a big difference: Trains can trigger a signal light to turn red or green. They do it just by rolling on a track.
Here’s how: Tracks have circuits that flow with electric current. The current causes a green light to stay on. The green light means that the track is clear, no trains in sight.
What happens when a train rolls up? The train’s wheels are metal, a good <#5963,7><!conductor> of electricity. The current goes through the wheels instead of through the track. This change in the current’s path flips <#5964,15><!switches> called relays. The flipped switches turn off the green light and turn on a red light. Red means “Watch out! There’s a train on the tracks!” No other train can pass through.
After the train rolls by, the electric current passes through the track again. The relay switches flip back to their original position. This triggers the light signal to change from red back to green.
A relay is a special kind of switch that flips itself in response to electric current. The relays that you’ll find in the ElectroLoft use an electric <#5969,20><!coil>. When current flows through the coil, it magnetically pulls on a lever to flip the switch.
