In engineering, electromechanics combines electrical and mechanical processes. 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.
Devices which carry out electrical operations by using moving parts are known as electromechanical. Strictly speaking, a manually operated switch is an electromechanical component, but the term is usually understood to refer to devices such as relays, which allow a voltage or current to control other, isolated voltages and currents by mechanically switching sets of contacts, solenoids, by which a voltage can actuate a moving linkage, vibrators, which convert DC to AC with vibrating sets of contacts, etc. Before the development of modern electronics, electromechanical devices were widely used in complex circuits, including electric typewriters and teletypes, and up to the complexity of an electromechanical digital computer.