Transistors, the tiny switches that flip on and off inside computer chips, have long been the domain of electricity. But scientists are beginning to develop chip components that run on light. Last ...

A transistor is a key component in electronics, often used as a switch or to amplify a signal from a sensor. NPN (negative-positive-negative) transistors are the most used transistor. An illustration ...

A teacher I know is stuck, with only npn transistors in the supply cupboard and the need to create a reversible motor drive for an Arduino project. Reversing ‘bridges’ have four switches (relay ...