Invented by Bell Laboratories scientists in 1947 and announced in 1948, the transistor allowed electronic equipment to become much, much smaller. The transistor is a device that transfers electronic signals across a resistor (it gets its name from transferring over a resistor). The device is smaller than the vacuum tube it replaced, requires less energy, generates less heat, and is more dependable and faster. The transistor radio was among the early innovations made possible by the 1948 invention, making radios truly wireless—and portable. Transistors, of which many types have been designed since their invention, are also used in computers (on the computer chip), and in numerous other consumer electronics. Another principal use is in the space and military industries where transistors are used in automatic control instrumentation for flight and guided missiles.