A transistor is a fundamental electronic component that controls the flow of electrical current in a circuit. It serves two main functions:

• Switch: A transistor can act as an electronic switch, turning current on or off in a circuit. When a small voltage or current is applied to one terminal (the base in a bipolar junction transistor, or the gate in a field-effect transistor), it allows a much larger current to flow between the other two terminals (collector and emitter, or drain and source). This switching action is the basis for digital logic in computers, where transistors represent binary states (on/off, or 1/0)

• Amplifier: A transistor can also amplify electrical signals. A small input current or voltage at one terminal can control a much larger current flowing through the other terminals, making weak signals stronger. This amplification is crucial in devices like radios, audio equipment, and sensors

Transistors are made from semiconductor materials (typically silicon) and have three terminals: emitter, base, and collector (for BJTs), or source, gate, and drain (for FETs). Their ability to switch and amplify signals makes them the building blocks of all modern electronic devices, including computers, smartphones, and countless other technologies