attention Look up Attention in Wiktionary, the free dictionary Attention is the cognitive process of selectively concentrating on one thing while ignoring other things. ...

A proportional control system is a type of linear feedback control system. A sensor attached to the process under control generates a feedback signal that measures the output of the system. (For example, in a furnace control system, the sensor would detect the temperature of the furnace, and the feedback signal would be a voltage representing that temperature.) The controller subtracts a set point (in our example, this would be a voltage representing the desired temperature) from the feedback signal to obtain a control signal that modifies the behaviour of the process. In an analogue control system, the subtraction is done by a differential amplifier; in a digital system, it is usually done by a microprocessor or a look-up table. In cybernetics and control theory, feedback is a process whereby some proportion or in general, function, of the output signal of a system is passed (fed back) to the input. ... A control system is a device or set of devices that manage the behavior of other devices. ... A sensor is a technological device or biological organ that detects, or senses, a signal or physical condition. ... Temperature is the physical property of a system which underlies the common notions of hot and cold; the material with the higher temperature is said to be hotter. ... In the physical sciences, potential difference is the difference in potential between two points in a conservative vector field. ... Simple form of a differential amplifier A differential amplifier is a type of an electronic amplifier that multiplies the difference between two inputs by some constant factor (the differential gain). ... Microprocessors, including an Intel 80486DX2 and an Intel 80386 A microprocessor (abbreviated as µP or uP) is an electronic computer central processing unit (CPU) made from miniaturized transistors and other circuit elements on a single semiconductor integrated circuit (IC) (aka microchip or just chip). ... In computer science, a lookup table is a data structure, usually an array or associative array, used to replace a runtime computation with a simpler lookup operation. ...

The proportional control system is more complex than a logic control system, but simpler than a proportional-integral-derivative (PID) control system. A Proportional-Integral-Derivative controller or PID is a standard feedback loop component in industrial control applications. ...

• A comparison with driving a car:

An on-off control is like driving a car with no brakes at full power and full speed until the target point is reached. Then the power is removed, suddenly and completely, the car reduces speed, coming to a stop finally after a large "overshoot".

A proportional control is like driving a car with no brakes until the target point is seen in the distance. From then on the power applied is proportional to the remaining distance to the target point, so that the car reduces speed gradually and reaches the target point with very little, if any, "overshoot".

See Also

• PID controller