What is a real transformer?

Dear Samarth,
I know you love transformer cars, but you wanted to know what is a real transformer, right?

Do you know that we can create electricity using magnets? When you pass electricity through a coil, then you create an invisible magnet. See the image below:

The image shows what happens when current is passed through the coil. The lines and arrows show the magnetic fields. The more turns that we add and the higher the current through the coil, the stronger is the invisible magnetic field. If we put iron rod inside this coil, the invisible magnetic field will convert this iron into a magnet. See this picture:

Similarly you can create current, when you pass a magnet through a coil. That's what we do in hydro-electric power plants and dynamos in cars (did you notice we never change batteries in real cars).

You create a transformer when you have two coils in an iron core one with more turns and other with less turns. When you pass current through one of the coils, the magnet generates current in the other coil. The following picture shows this:

Real simple right?

Love,
Papa