What Car Q&A - What is a supercharger?

I was reading an article on your site the other day about a new Volkswagen engine that uses a supercharger and a turbocharger. What's the difference between the two?
A Dwyer

You're talking about the new TSI engine from Volkswagen which we featured here.

Both force more air into the cylinders of the engine to increase power output by compressing it. A supercharger is driven by a belt or chain connected to the engine's crankshaft, while a turbocharger's compressor is powered by the flow of air or exhaust gas.

A supercharger is quicker to respond than a turbocharger, which is why Volkswagen's engine uses it at lower engine speeds. As engine speed increases there's gradually less need for the supercharger until around 3000rpm when the turbocharger is exclusively used.