Vacuum tubes are the brain cells of modern technology. Each year, as machines take on more complex jobs, more & more vacuum tubes are needed. But they are tricky to manufacture: they are usually both bulky and fragile. They have to warm up before they can start operating, and they need a continuous current to keep their filaments hot. The men who design electronic nervous systems would like a vacuum tube without these faults.
Last week Bell Telephone Laboratories demonstrated a small, simple device that can do many of the jobs now done by vacuum tubes. Called a "Transistor," it has no vacuum, no glass envelope. It requires no heating current and can start working immediately without a warmup.
The Transistor is a slim metal cylinder about an inch long. Inside are two hair-thin wires whose points press, two-thousandths of an inch apart, on a pinhead of germanium. A feeble current in the "input" wire controls a much larger current flowing from the "output" wire. Such "amplification" is the essential property of vacuum tubes. The Transistor works on a different principle (by changing the conductivity of the germanium), but it amplifies the input current as much as 100 times.
Transistors are not in production yet, but Bell scientists, to show what their little brain cells can do, demonstrated a radio receiver with vacuum tubes replaced by Transistors. Though not very powerful, it worked fine. Probably the Transistor's first practical assignment will be to amplify currents in telephone circuits, a job now done by vacuum tubes.