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Do you have a doorbell at your house? Maybe you live in an apartment and have a bunch of doorbells – and maybe even an intercom – at your entrance. You probably don’t give it much thought, but doorbells make life a lot easier. With a simple push of a button, your friends, neighbors, and even door-to-door salespeople can announce their presence and request entry into your humble abode.

The heart of a doorbell is an electromagnet. Electromagnets are coils of wire wrapped around a small piece of magnetic metal. When electricity passes through the wire, it creates a magnetic field around the wire.

When you press a doorbell button, you complete an electrical circuit that allows household electricity to flow through the doorbell’s internal electromagnet. The magnetic field generated by the electromagnet is then used to power a mechanism that creates the doorbell sound.

Doorbells are low-voltage devices. This means they require relatively little energy to operate. An important part of a doorbell mechanism is the transformer. The transformer converts a regular 120-volt household current to the lower voltage (usually somewhere between 6-16 volts) required by the doorbell.