Lecture 5 - Mixers, meters and molecules
Most people are aware that modern computing and electronic devices rely on the element silicon. The size of a silicon integrated circuit or chip as it is known is typically only a few millimetres square and a tenth of a millimetre thick. One of the biggest growth-areas for this technology will be as control chips for use with electric motors.
The first electric motor was built by Faraday in 1821. The motors of today derive from Faraday's design, and operate at speeds which are largely determined by the frequency of the a.c. mains supply. In many cases these speeds are not ideal for use in domestic appliances such as washing machines, food mixers and electrical drills. In 1840 Faraday's good friend Wheatstone also built a motor, his was called an electromagnetic engine. It was simple, quiet and had variable speeds but was hard to control. The application of silicon microelectronics to power control has largely overcome this problem and has led to a resurgence of interest in Wheatstone's engine which is now known as a switched reluctance motor.
Silicon technology is also important in a very different way in miniaturizing sensors and actuators. The principle that is used is based on the chemical etching of silicon. An example of this class of device is a domestic microengineered gas meter.
Only a modest diminution in the size of electronic circuit components is required before the scale of individual molecules is reached. Next century should herald the intrcxluction of the supermolecular computer based on organic molecules. It is important to recognize, however, that organic materials are already proving useful in the home environment and are performing roles quite distinct from those occupied by silicon or other inorganic materials. The best example of a molecular electronic device is that of a liquid crystal display television screen. Organic molecules also exhibit piezo-electric (pressure-sensitive) effects, change colour when exposed to light (photochromic), react specifically with certain fluids and gases, and conduct well in one dimension. All these interesting materials can be exploited in the home of the future.
About the 1988 CHRISTMAS LECTURES
Professor Gareth Roberts (1940-2007), then of Thorn EMI plc and the University of Oxford, and later Sir Gareth, presents the 1988 CHRISTMAS LECTURES titled 'The Home of the Future'. The impact of modern developments in electronics, materials and communications technology is becoming increasingly apparent in the home. There are numerous examples of innovative products that have arisen due to a combination of scientific progress and market demands. Many other exciting ideas are now emerging from industrial and academic laboratories and will play a significant role in homes during the next decade. These will be discussed in this series of lectures together with classic discoveries and inventions in related areas.