In engineering, electromechanics combines the sciences of electromagnetism, of electrical engineering and mechanics. Mechanical engineering in this context refers to the larger discipline which includes chemical engineering, and other related disciplines. Electrical engineering in this context also encompasses software engineering, computer engineering, and other related fields. This refers to the three major engineering disciplines of electrical engineering, mechanical engineering and civil engineering under which all other engineering disciplines are classified.
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Relays originated with telegraphy as electromechanical devices used to regenerate telegraph signals.
The Strowger switch, Panel switch and similar ones were widely used in early automated telephone exchanges. Crossbar switches were first widely installed in the middle 20th century in Sweden, the United States and Britain, and quickly spread to the rest of the world. The electromechanical television systems of the late 19th century were less successful.
Electric typewriters developed, up to the 1980s, as "power-assisted typewriters". They contained a single electrical component in them, the motor. Where the keystroke had previously moved a typebar directly, now it engaged mechanical linkages that directed mechanical power from the motor into the typebar. This was also true of the forthcoming IBM Selectric. At Bell Labs, in the 1940s, the Bell Model V computer was developed. It was an electromechanical relay-based monster with cycle times in seconds. In 1968 Garrett AiResearch was invited to produce a digital computer to compete with electromechanical systems then under development for the main flight control computer in the US Navy's new F-14 Tomcat fighter. Garrett created what is arguably the first complete microprocessor when it came up with the Central Air Data Computer for this project.
Common items, which in the 20th century would have used electromechanical devices for control, today use a less expensive and more effective standard integrated microcontroller circuit containing a few million transistors and a computer program to carry out the same task through logic. Such chips have replaced most electromechanical devices, are used in most simple feedback control systems, and appear in huge numbers in everything from traffic lights to washing machines, though the latter case, as others where mechanical motion is involved, requires that triacs control mechanical electric actuators.