100 YEARS AGO

The proposed application of electrical power for mounting plays at Drury Lane, on the lines advocated by Mr. Edwin O. Sachs, has now taken a tangible form in the completion of the first section of the stage installation in time for the impending pantomime. Mr Sachs' present work refers principally to the stage floor and its movability in sections above and below the footlights. The total area now already movable by mechanical power exceeds 1200 square feet. The electrical appliances just completed take the form of so-called “bridges,” each working independently. ⃛ They can travel about 20 feet vertically.

From Nature 29 December 1898.

50 YEARS AGO

J. Bardeen and W. H. Brattain, of the Bell Telephone Laboratories, in the course of general investigation, initiated and directed by W. H. Shockley, on the properties of semiconductors, have developed a new three-element electronic device, called by them a ‘transistor’ (transfer-resistor) or ‘semi-conductor triode’. This can be employed as an amplifier or oscillator and can replace the vacuum triode in most electronic circuits. The device, which consists of a metal cylinder, about an inch long and of the thickness of a pencil, containing the germanium and its three electrodes, was demonstrated with great success recently at a Press conference in New York. ⃛ In place of the single ‘cat's whisker’ of the crystal rectifier, two fine wires (both tungsten and phosphor-bronze have been used) make contact with the upper surface of the germanium block. These electrodes, the emitter and collector, are about 0.005-0.025 cm apart. The third electrode, which is a large-area low resistance contact, makes contact with the base of the block. ⃛ Amplifications up to 100 times, that is to say, a gain of 20 decibels, have been obtained. The transistor uses less power than a vacuum tube, has an output of 25 milliwatts and can operate at frequencies up to 10 megacycles per second. ⃛ The transistor is not yet in production, but its simplicity, small size, performance, long life, and probably low cost when mass-produced, should find many applications in all forms of electronic equipment.

From Nature 25 December 1948.