What is a central bank and what does it do?
The central bank is the entity that has a monopoly on the production and distribution of official money in a nation or block of countries.
In turn, it is the institution that dictates monetary policy to regulate the money supply in the economy. It is an entity independent of political power. For that reason, their decisions do not depend directly on the government in power, but on a directory.
This body, however, is sometimes appointed by another institution such as parliament, so there is always the possibility of political interference.