ELECTROMECHANICS

In engineering, electromechanics combines electrical and mechanical processes. Devices which carry out electrical operations by using moving parts are known as electromechanical. Strictly speaking, a manually operated switch is an electromechanical component. The term however 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 by which a voltage can actuate a moving linkage. Relays originated with telegraphy as electromechanical devices used to regenerate telegraph signals. 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.

Electromechanical logic gates can be build with relays. The Z3 and the Z4 were electromechanical machines which employed relays in all of their functional units. In contrast the Z2 used both mechanical and electromechanical means for different functional units. The Assembly Line Self-Replicating Systems envisioned by Konrad Zuse are electromechanical constructions.

cf. Wikipedia