John Bardeen was the winner of the Nobel prize, not once but twice! The only person in the history of the prize to do so. His first Nobel Prize was awarded for the transistor, his second for his work in superconductivity.
Transistors are commonly used in digital circuits as electronic switches which can be either in an "on" or "off" state, both for high-power applications such as switched-mode power supplies and for low-power applications such as logic gates.
