There is a electromagnetic coil with an open centre or tube through it. There is a iron rod that is at one end of the coil. The bar also has a spring on it. When the button is pushed the coil is activated and pulls the rod through the coil hitting the a tube causing the ding part of the chime. Then when the button is released the coil is released and the spring pulls the bar back hitting to make the dong part of the chime.

Speakers are made by putting a one layer coil of wire, wound onto a tube, into a magnetic field. The end of the tube is attached to the center of the paper cone of the speaker. When current is passed through the coil, a force is created on the coil, causing it and the tube to move within the magnetic field. When the current reverses direction, the coil and tube move in the opposite direction.

By running a current through a wire coiled around a steel nail you can create a magnetic field. It can lift magnetic materials. The more coils and the more powerful current passed through the wire the stronger it will become but careful because to much power and the wire might get a bit hot!

The magnetic lock works by using electromagnetis m. What happens is an electromagnet attracts a magnetic substance with a large enough force to stop the door from being opened.

A relay is a simple electromechanical switch made up of an electromagnet and a set of contacts. Relays are found in all sorts of devices.