Transistors
A Miniature Miracle:
Greenledge Studios
T h i n k hard, work
soft
Transistors keep getting smaller and smaller. This allows newer, more powerful computers to be made using the latest technology without increasing the typical size of a computer. Wafers of silicon are used to build integrated circuits incorporating millions of transistors onto a single silicon chip. Chips must be handled delicately to prevent damage to the tiny wires which connect the internal circuit to its outer sheath. These chips in turn serve specialized purposes such as data processing and data storage. New devices are being developed constantly, while the prices for existing technology keep going down as the manufacturing process becomes refined, thereby increasing the yield. A higher yield means fewer non-functioning circuits on each silicon wafer in any production run.
Transistor technology is electronically rugged. This means that, while it may be sensitive to mechanical shock, it is not particularly susceptible to damage from high voltages. Lightning is an exception to this (static electricity, representing thousands of volts, is often said to be capable of rendering sensitive circuits such as computer memory and CPU's useless during installation). The reason that transistor technology is so rugged is that the transistors themselves are normally protected by resistors which limit the current flow, thereby preventing meltdown due to overheating.
Transistors can be used digitally and in switching applications. In other words, while analog devices such as amplifiers also use transistors, computers use transistors digitally by simply turning them on and off. The "on" state is equivalent to a digital "1" and the "off" state is equivalent to a digital "0". This is a switch. The voltage at which a transistor turns "on" is about .7 Volts in silicon. Germanium circuits require only .3 Volts to turn them "on", but germanium is not used as often as silicon in integrated circuits because of scarcity. When the voltage reaches the "on" level, the transistor turns "on". In the "on" state the transistor provides essentially no resistance to current flow, which is why resistors are required to prevent overheating. Because of the protection afforded by resistors, there is no worry about damage to circuits from accidentally connecting a higher voltage to a device, unless the voltage is many times higher than the specified voltage.