Transistors. Fingers hold transistors from the 1970s (upper) and 1960s (lower). Transistors have many uses in electronic equipment including elect- rical amplification & signal processing. Transist- ors have three wires attached to them - called the base, collector & emitter. These are attached to sections of semiconductor in the transistor which have precise levels of impurities to determine their electrical properties. The amplification of the current from emitter to collector is deter- mined by the voltage of the base wire. Transistors have allowed the miniaturisation of electronic components. The first transistor was invented on 23 December 1947 by Bardeen, Brattain & Shockley.