Overnight target rates and inflation
One of the major targets of every central bank is a low and stable inflation. Its main control variable is the overnight interest rate target and mechanism which allows the target to affect inflation is known as transmission mechanism. A brief account of the transmission mechanism looks like this:
1. When central bank target rate increases, other interest rates in economy will increase (and money supply will decrease, however that isn't important here).
2. With higher interest rates, it's more expensive to borrow and more advantageous to save. Hence, investment and consumption will decrease (we say that central bank 'cools off' the economy).
3. As consumption and investment fall, GDP is reduced and unemployment will rise. This will cause inflation and growth rate in wages to fall.