Regulator (automatic control)

Inautomatic control,aregulatoris a device which has the function of maintaining a designated characteristic. It performs the activity of managing or maintaining a range of values in a machine. The measurable property of a device is managed closely by specified conditions or an advance set value; or it can be a variable according to a predetermined arrangement scheme. It can be used generally to connote any set of various controls or devices for regulating or controlling items or objects.

Examples are avoltage regulator(which can be atransformerwhose voltage ratio of transformation can be adjusted, or anelectronic circuitthat produces a defined voltage), apressure regulator,such as adiving regulator,which maintains its output at a fixed pressure lower than its input, and a fuel regulator (which controls the supply of fuel).

Regulators can be designed to control anything from gases or fluids, to light or electricity. Speed can be regulated by electronic, mechanical, orelectro-mechanicalmeans. Such instances include;

Electronic regulators as used in modern railway sets where the voltage is raised or lowered to control the speed of the engine
Mechanical systems such asvalvesas used in fluid control systems. Purely mechanical pre-automotive systems included such designs as theWatt centrifugal governorwhereas modern systems may have electronic fluid speed sensing components directingsolenoidsto set the valve to the desired rate.
Complex electro-mechanical speed control systems used to maintain speeds in modern cars (cruise control) - often including hydraulic components,
An aircraft engine'sconstant speed unitchanges the propeller pitch to maintain engine speed.

See also