If you've ever wondered how to control the headlight of a car from a microcontroller, a MOSFET is what you need.
The FQP27P06 is a very common MOSFET with very low on-resistance and a control voltage (aka gate voltage) that is compatible with most 5V microcontroller or mechanical switches.
This allows you to control high-power devices with very low-power control mechanisms.

Documents:

• Datasheet