So imagine you have a toy car that goes really fast. Sometimes you need it to go slower or faster depending on how you want to play with it. A tap changer is like a switch on the car that you can use to change how fast it goes.
But instead of a toy car, we're talking about something called a transformer. A transformer is a machine that helps change the voltage of electricity. It's kind of like how you can change the volume on your TV.
Now sometimes the transformer needs to change the voltage more than just turning a knob. That's where the tap changer comes in. It's like a special switch that can be used to make bigger changes to the voltage of the transformer.
Think of it like how you can change the speed of your toy car by pressing a button. But on a transformer, you don't press a button, a special machine does it for you. And that's what a tap changer is, a special switch that helps make changes to the voltage of a transformer.