The alternator consists of two parts, the alternator itself and the voltage regulator that is bolted to the rear of the alternator. Either part could fail and the voltage regulator can be replaced on its own if required.
Failure of the regulator is most often called a alternator failure by mistake.

To the detriment of all of us many company's have sourced their products from China, I have decided to cut out the middle man and buy direct from China if possible. You can buy the same equivalent thing that is sold under a familiar name for less under a Chinese brand name and in many cases the price includes shipping.
These western companies showed the Chinese how to make these things and they learnt well, just like the Japanese did. Serves them right they gave away our jobs, we owe these companies nothing. I say **** them all. If an item says made in China you can likely buy something equal direct from China and save.
Use eBay and filter out all countries but China. You will be amazed what is there.
Rant over.