Historical background of electronics
The introduction of vacuum tubes in the early twentieth century led to the rapid growth of modern electronics. With these devices made possible the manipulation of signals, which could not be done in the old telegraph and telephone circuits, or with the first transmitters using high-voltage sparks to generate radio waves. For example, with vacuum tubes could amplify radio signals and sound weak, and also potentially overlapping audio signals to radio waves. The development of a wide variety of tubes, designed for specialized functions, enabled the rapid advancement of technology for communication radio before the Second World War, and the development of early computers, during the war and shortly afterwards.
Today, the transistor, invented in 1948, has almost completely replaced the vacuum tube in most applications. By incorporating a set of materials semiconductor and electrical contacts, the transistor allows the same functions as the vacuum tube, but at a cost, weight and power lower, and greater reliability. The subsequent progress in semiconductor technology, attributable in part to the intensity of the investigations associated with space exploration initiative led to the development in the 1970s, the integrated circuit. These devices can contain hundreds of thousands of transistors on a small piece of material, allowing the construction of complex electronic circuits such as microcomputers or microcomputers, audio and video equipment, and satellites for communications.