Transistors are essential components in modern electronics, acting as switches or amplifiers for electrical signals. They are made from semiconductor materials like silicon and can control the flow of current, making them crucial for devices such as computers, smartphones, and radios. Invented in the 1940s, transistors replaced vacuum tubes, leading to smaller, more efficient electronic devices. Their ability to amplify signals has revolutionized technology, enabling advancements in telecommunications and computing. Today, billions of transistors are found in microprocessors, showcasing their importance in the digital age.