What is a transistor?

A transistor is a semiconductor device that is used to amplify or switch electronic signals. It is made up of three layers of alternating N-type and P-type semiconductors. The three layers form two junctions: the emitter-base junction and the collector-base junction. The transistor has three terminals - the emitter, the base, and the collector. The flow of current between the emitter and collector is controlled by the voltage applied to the base. Transistors are widely used in electronic circuits for amplification, switching, and signal processing.