Transformer

The transformation relationship is (n2/n1)^2=v2/v1 so the number of turns in each part is proportional to the transformed voltage

There are many different uses and many different types of transfomers, Like there are microwave transformers, that amplifies 120v AC to around 2200v AC with only a few miliamps, another example would be the ones like in your computer power supply, or any power supply really, that have a certain number of windings to produce a voltage an amperage low enough to where it can be utilized properly by whatever its supplying power too. There are many many more types, but those are some examples of what basic transformers do

so what you have here is what's known as a stepdown transformer, wherr the output voltage is lower, but the amperage is higher

There are three types of transformers, step up, step down, and isolation. Step up increases the voltage but the current drops, and are used for things like microwaves like sigma said. The step down transformers step down voltage and current increases through the secondary because of this. Most common uses for this are wall adapters where they take 120 vac Rms, and step it down to about 12 vac Rms, then it can be rectified into dc and used to power low power devices, i.e. Your phone or a computer. Also used in power distribution networks where very high voltages are transmitted across large distances i.e. Power lines, then stepped down at sub stations, then sent to the transformer for your house where it is stepped down from 440 vac Rms to 120 vac Rms, and 220 vac Rms for your dryer. Then isolation transformers do not convert voltage or current. They are mainly used in applications where the load could be shorted, and it not short the power supply and damage it, or when noise will be produced by the electronics and you don't want that to be put back into the generator or transmission lines.

That's very new to me when read your comments about Transformer and I understood. Thank you, all of you!