Start with a switch
A transistor is a semiconductor device that can control electrical current. It can work as a switch or an amplifier. In digital circuits, carefully designed combinations of transistors represent and process binary states.
Control without a moving lever
In a field-effect transistor, a voltage applied to the gate changes how easily current can flow through a channel. The illustration uses an abstract switch: real transistor structures are more complex.
From switches to operations
Networks of transistors form logic gates. Combining gates makes more complex circuits possible, including circuits that perform arithmetic. A computer’s abilities emerge from organised circuits and instructions, rather than from an individual transistor “understanding” information.
A long evolution
Bardeen and Brattain demonstrated a working point-contact transistor at Bell Labs in December 1947. Modern integrated circuits differ enormously from that early device, but the ability to control signals with semiconductor structures remains fundamental.
Sources & further reading
Sources checked 13 November 2026. These organisations provide reference material and do not endorse this website.
