What’s inside a relay?

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Top down view of relay showing the circuit diagram of what is inside.
Top down view of relay showing the circuit diagram of what is inside.

Ever wonder what’s inside a RELAY?

These little electrically-powered switches allow a low power circuit to control a high power circuit. They’re a big part of a lot of appliances that have a power button and you can often hear them switch on with an audible click.

This one is from my car and it is used to flash the lights when the headlights aren’t on. The big copper coil is an electromagnet. When the current through the coil is on, it creates a magnetic field that moves that little arm to close an electrical circuit.

Underside of the relay with the electrical contacts. It's not visible here, but each is labeled with a standardized number.
Underside of the relay with the electrical contacts. It’s not visible here, but each is labeled with a standardized number.
Relay with plastic cover removed.
Getting the plastic cap off without destroying the whole thing (or my hands) was a real challenge.
Switch arm component of relay.
Switch arm component of relay.
Close up fiew of the switch arm component of relay to show electrical contacts.
Close up fiew of the switch arm component of relay to show electrical contacts.
Looking down switch arm to show the air gap between the contacts.
Looking down switch arm to show the air gap between the contacts.
Top down view of relay showing contact points.
Top down view of relay showing contact points.

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