114 relations: Addition, Adrenal cortex, Adrenocorticotropic hormone, Air conditioning, Amplifier, Analog computer, Asymptotic gain model, Audio signal, Automatic gain control, Automatic stabilizer, Ballcock, Baroreflex, Bell Labs, Biochemistry, Biofeedback, Biology, Blood pressure, Blood sugar level, Carburetor, Centrifugal governor, Chaos theory, Climate change feedback, Control engineering, Control system, Control theory, Cornelis Drebbel, Corticotropin-releasing hormone, Cortisol, Ctesibius, Cybernetics, Cybernetics: Or Control and Communication in the Animal and the Machine, Dashpot, Demand, Demodulation, Derivative, Diabetes mellitus, Distortion, Ecological economics, Endocrine system, Engineering, Erythropoiesis, Exponential growth, Feedback, FM broadcasting, Frequency divider, Frequency multiplier, Fuel injection, Function (mathematics), George Soros, Glucocorticoid, ..., Glucose, Harold Stephen Black, Harry Nyquist, Herman Daly, Heterodox economics, Homeostasis, Hormone, Human body, Hypothalamus, Instability, Integral, Investor, Invisible hand, James Clerk Maxwell, James Watt, Karl Küpfmüller, List of types of equilibrium, Logarithm, Loop gain, Low-pass filter, Mainstream economics, Mathematics, Mechanical equilibrium, Mechanics, Millstone, Negative-feedback amplifier, Norbert Wiener, Nyquist stability criterion, Open-loop controller, Operational amplifier, Organism, Oscillation, Perceptual control theory, Phase-locked loop, Physiology, PID controller, Pituitary gland, Positive feedback, Process variable, Propagation delay, Real gross domestic product, Refrigerator, Regenerative circuit, Regulator (automatic control), Sensor, Servomechanisms, Setpoint (control system), Sound, Speed, Stability criterion, Stability theory, Steam engine, Steering engine, Step response, Subtraction, Supply (economics), Supply and demand, System dynamics, Valence (psychology), Voltage divider, W. Ross Ashby, Water clock, Windmill, World Bank. Expand index (64 more) » « Shrink index
Addition (often signified by the plus symbol "+") is one of the four basic operations of arithmetic; the others are subtraction, multiplication and division.
Situated along the perimeter of the adrenal gland, the adrenal cortex mediates the stress response through the production of mineralocorticoids and glucocorticoids, such as aldosterone and cortisol, respectively.
Adrenocorticotropic hormone (ACTH, also adrenocorticotropin, corticotropin) is a polypeptide tropic hormone produced by and secreted by the anterior pituitary gland.
Air conditioning (often referred to as AC, A/C, or air con) is the process of removing heat and moisture from the interior of an occupied space, to improve the comfort of occupants.
An amplifier, electronic amplifier or (informally) amp is an electronic device that can increase the power of a signal (a time-varying voltage or current).
An analog computer or analogue computer is a form of computer that uses the continuously changeable aspects of physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved.
The asymptotic gain model (also known as the Rosenstark method) is a representation of the gain of negative feedback amplifiers given by the asymptotic gain relation: where T is the return ratio with the input source disabled (equal to the negative of the loop gain in the case of a single-loop system composed of unilateral blocks), G∞ is the asymptotic gain and G0 is the direct transmission term.
An audio signal is a representation of sound, typically as an electrical voltage for analog signals and a binary number for digital signals.
Automatic gain control (AGC), also called automatic volume control (AVC), is a closed-loop feedback regulating circuit in an amplifier or chain of amplifiers, the purpose of which is to maintain a suitable signal amplitude at its output, despite variation of the signal amplitude at the input.
In macroeconomics, automatic stabilizers are features of the structure of modern government budgets, particularly income taxes and welfare spending, that act to dampen fluctuations in real GDP.
A ballcock (also balltap or float valve) is a mechanism or machine for filling water tanks, such as those found in flush toilets, while avoiding overflow and (in the event of low water pressure) backflow.
The baroreflex or baroreceptor reflex is one of the body's homeostatic mechanisms that helps to maintain blood pressure at nearly constant levels.
Nokia Bell Labs (formerly named AT&T Bell Laboratories, Bell Telephone Laboratories and Bell Labs) is an American research and scientific development company, owned by Finnish company Nokia.
Biochemistry, sometimes called biological chemistry, is the study of chemical processes within and relating to living organisms.
Biofeedback is the process of gaining greater awareness of many physiological functions primarily using instruments that provide information on the activity of those same systems, with a goal of being able to manipulate them at will.
Biology is the natural science that studies life and living organisms, including their physical structure, chemical composition, function, development and evolution.
Blood pressure (BP) is the pressure of circulating blood on the walls of blood vessels.
The blood sugar level, blood sugar concentration, or blood glucose level is the amount of glucose present in the blood of humans and other animals.
A carburetor (American English) or carburettor (British English; see spelling differences) is a device that mixes air and fuel for internal combustion engines in the proper ratio for combustion.
A centrifugal governor is a specific type of governor with a feedback system that controls the speed of an engine by regulating the amount of fuel (or working fluid) admitted, so as to maintain a near-constant speed, irrespective of the load or fuel-supply conditions.
Chaos theory is a branch of mathematics focusing on the behavior of dynamical systems that are highly sensitive to initial conditions.
Climate change feedback is important in the understanding of global warming because feedback processes may amplify or diminish the effect of each climate forcing, and so play an important part in determining the climate sensitivity and future climate state.
Control engineering or control systems engineering is an engineering discipline that applies automatic control theory to design systems with desired behaviors in control environments.
A control system manages, commands, directs, or regulates the behavior of other devices or systems using control loops.
Control theory in control systems engineering deals with the control of continuously operating dynamical systems in engineered processes and machines.
Cornelis Jacobszoon Drebbel (1572 – 7 November 1633) was a Dutch engineer and inventor.
Corticotropin-releasing hormone (CRH) (also known as corticotropin-releasing factor (CRF) or corticoliberin; corticotropin may also be spelled corticotrophin) is a peptide hormone involved in the stress response.
Cortisol is a steroid hormone, in the glucocorticoid class of hormones.
Ctesibius or Ktesibios or Tesibius (Κτησίβιος; fl. 285–222 BC) was a Greek inventor and mathematician in Alexandria, Ptolemaic Egypt.
Cybernetics is a transdisciplinary approach for exploring regulatory systems—their structures, constraints, and possibilities.
Cybernetics: Or Control and Communication in the Animal and the Machine is a book written by Norbert Wiener and published in 1948.
A dashpot is a mechanical device, a damper which resists motion via viscous friction.
In economics, demand is the quantities of a commodity or a service that people are willing and able to buy at various prices, over a given period of time.
Demodulation is extracting the original information-bearing signal from a carrier wave.
The derivative of a function of a real variable measures the sensitivity to change of the function value (output value) with respect to a change in its argument (input value).
Diabetes mellitus (DM), commonly referred to as diabetes, is a group of metabolic disorders in which there are high blood sugar levels over a prolonged period.
Distortion is the alteration of the original shape (or other characteristic) of something.
Ecological economics (also called eco-economics, ecolonomy or bioeconomics of Georgescu-Roegen) is both a transdisciplinary and an interdisciplinary field of academic research addressing the interdependence and coevolution of human economies and natural ecosystems, both intertemporally and spatially.
The endocrine system is a chemical messenger system consisting of hormones, the group of glands of an organism that carry those hormones directly into the circulatory system to be carried towards distant target organs, and the feedback loops of homeostasis that the hormones drive.
Engineering is the creative application of science, mathematical methods, and empirical evidence to the innovation, design, construction, operation and maintenance of structures, machines, materials, devices, systems, processes, and organizations.
Erythropoiesis (from Greek 'erythro' meaning "red" and 'poiesis' meaning "to make") is the process which produces red blood cells (erythrocytes).
Exponential growth is exhibited when the rate of change—the change per instant or unit of time—of the value of a mathematical function is proportional to the function's current value, resulting in its value at any time being an exponential function of time, i.e., a function in which the time value is the exponent.
Feedback occurs when outputs of a system are routed back as inputs as part of a chain of cause-and-effect that forms a circuit or loop.
FM broadcasting is a method of radio broadcasting using frequency modulation (FM) technology.
A frequency divider, also called a clock divider or scaler or prescaler, is a circuit that takes an input signal of a frequency, f_, and generates an output signal of a frequency: f_.
In electronics, a frequency multiplier is an electronic circuit that generates an output signal whose output frequency is a harmonic (multiple) of its input frequency.
Fuel injection is the introduction of fuel in an internal combustion engine, most commonly automotive engines, by the means of an injector.
In mathematics, a function was originally the idealization of how a varying quantity depends on another quantity.
George Soros, Hon (Soros György,; born György Schwartz; August 12, 1930) is a Hungarian-American investor, business magnate, philanthropist, political activist and author.
Glucocorticoids are a class of corticosteroids, which are a class of steroid hormones.
Glucose is a simple sugar with the molecular formula C6H12O6.
Harold Stephen Black (April 14, 1898 – December 11, 1983) was an American electrical engineer, who revolutionized the field of applied electronics by inventing the negative feedback amplifier in 1927.
Harry Nyquist (born Harry Theodor Nyqvist,; February 7, 1889 – April 4, 1976) was a Swedish-born American electronic engineer who made important contributions to communication theory.
Herman Edward Daly (born July 21, 1938) is an American ecological and Georgist economist and emeritus professor at the School of Public Policy of University of Maryland, College Park in the United States.
Heterodoxy is a term that may be used in contrast with orthodoxy in schools of economic thought or methodologies, that may be beyond neoclassical economics.
Homeostasis is the tendency of organisms to auto-regulate and maintain their internal environment in a stable state.
A hormone (from the Greek participle “ὁρμῶ”, "to set in motion, urge on") is any member of a class of signaling molecules produced by glands in multicellular organisms that are transported by the circulatory system to target distant organs to regulate physiology and behaviour.
The human body is the entire structure of a human being.
The hypothalamus(from Greek ὑπό, "under" and θάλαμος, thalamus) is a portion of the brain that contains a number of small nuclei with a variety of functions.
In numerous fields of study, the component of instability within a system is generally characterized by some of the outputs or internal states growing without bounds.
In mathematics, an integral assigns numbers to functions in a way that can describe displacement, area, volume, and other concepts that arise by combining infinitesimal data.
An investor is a person that allocates capital with the expectation of a future financial return.
The invisible hand is a term used by Adam Smith to describe the unintended social benefits of an individual's self-interested actions.
James Clerk Maxwell (13 June 1831 – 5 November 1879) was a Scottish scientist in the field of mathematical physics.
James Watt (30 January 1736 (19 January 1736 OS) – 25 August 1819) was a Scottish inventor, mechanical engineer, and chemist who improved on Thomas Newcomen's 1712 Newcomen steam engine with his Watt steam engine in 1781, which was fundamental to the changes brought by the Industrial Revolution in both his native Great Britain and the rest of the world.
Karl Küpfmüller (6 October 1897 – 26 December 1977) was a German electrical engineer, who was prolific in the areas of communications technology, measurement and control engineering, acoustics, communication theory and theoretical electro-technology.
This is a list of various types of equilibrium, the condition of a system in which all competing influences are balanced.
In mathematics, the logarithm is the inverse function to exponentiation.
In electronics and control system theory, loop gain is the sum of the gain, expressed as a ratio or in decibels, around a feedback loop.
A low-pass filter (LPF) is a filter that passes signals with a frequency lower than a certain cutoff frequency and attenuates signals with frequencies higher than the cutoff frequency.
Mainstream economics may be used to describe the body of knowledge, theories, and models of economics, as taught across universities, that are generally accepted by economists as a basis for discussion.
Mathematics (from Greek μάθημα máthēma, "knowledge, study, learning") is the study of such topics as quantity, structure, space, and change.
In classical mechanics, a particle is in mechanical equilibrium if the net force on that particle is zero.
Mechanics (Greek μηχανική) is that area of science concerned with the behaviour of physical bodies when subjected to forces or displacements, and the subsequent effects of the bodies on their environment.
Millstones or mill stones are stones used in gristmills, for grinding wheat or other grains.
A Negative-feedback amplifier (or feedback amplifier) is an electronic amplifier that subtracts a fraction of its output from its input, so that negative feedback opposes the original signal.
Norbert Wiener (November 26, 1894 – March 18, 1964) was an American mathematician and philosopher.
In control theory and stability theory, the Nyquist stability criterion, discovered by Swedish-American electrical engineer Harry Nyquist at Bell Telephone Laboratories in 1932, on is a graphical technique for determining the stability of a dynamical system.
In an open-loop controller, also called a non-feedback controller, the control action from the controller is independent of the "process output", which is the process variable that is being controlled.
An operational amplifier (often op-amp or opamp) is a DC-coupled high-gain electronic voltage amplifier with a differential input and, usually, a single-ended output.
In biology, an organism (from Greek: ὀργανισμός, organismos) is any individual entity that exhibits the properties of life.
Oscillation is the repetitive variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states.
Perceptual control theory (PCT) is a model of behavior based on the principles of negative feedback, but differing in important respects from engineering control theory.
A phase-locked loop or phase lock loop abbreviated as PLL is a control system that generates an output signal whose phase is related to the phase of an input signal.
Physiology is the scientific study of normal mechanisms, and their interactions, which work within a living system.
A proportional–integral–derivative controller (PID controller or three term controller) is a control loop feedback mechanism widely used in industrial control systems and a variety of other applications requiring continuously modulated control.
An explanation of the development of the pituitary gland (Hypophysis cerebri) & the congenital anomalies. In vertebrate anatomy, the pituitary gland, or hypophysis, is an endocrine gland about the size of a pea and weighing in humans.
Positive feedback is a process that occurs in a feedback loop in which the effects of a small disturbance on a system include an increase in the magnitude of the perturbation.
A process variable, process value or process parameter is the current measured value of a particular part of a process which is being monitored or controlled.
Propagation delay is a technical term that can have a different meaning depending on the context.
Real Gross Domestic Product (real GDP) is a macroeconomic measure of the value of economic output adjusted for price changes (i.e., inflation or deflation).
A refrigerator (colloquially fridge, or fridgefreezer in the UK) is a popular household appliance that consists of a thermally insulated compartment and a heat pump (mechanical, electronic or chemical) that transfers heat from the inside of the fridge to its external environment so that the inside of the fridge is cooled to a temperature below the ambient temperature of the room.
A regenerative circuit is an amplifier circuit that employs positive feedback (also known as regeneration); some of the output of the amplifying device is applied to its input without phase inversion, which reinforces the signal, increasing the amplification.
In automatic control, a regulator is a device which has the function of maintaining a designated characteristic.
In the broadest definition, a sensor is a device, module, or subsystem whose purpose is to detect events or changes in its environment and send the information to other electronics, frequently a computer processor.
Servomechanisms, Inc. was a Cold war era U.S. defense sub-contractor, which developed precision sub-systems for high performance jet aircraft, guided missiles and ballistic missiles.
In cybernetics and control theory, a setpoint (also set point, set-point) is the desired or target value for an essential variable, or process value of a system.
In physics, sound is a vibration that typically propagates as an audible wave of pressure, through a transmission medium such as a gas, liquid or solid.
In everyday use and in kinematics, the speed of an object is the magnitude of its velocity (the rate of change of its position); it is thus a scalar quantity.
In control theory, and especially stability theory, a stability criterion establishes when a system is stable.
In mathematics, stability theory addresses the stability of solutions of differential equations and of trajectories of dynamical systems under small perturbations of initial conditions.
A steam engine is a heat engine that performs mechanical work using steam as its working fluid.
A steering engine is a power steering device for ships.
The step response of a system in a given initial state consists of the time evolution of its outputs when its control inputs are Heaviside step functions.
Subtraction is an arithmetic operation that represents the operation of removing objects from a collection.
In economics, supply is the amount of something that firms, consumers, labourers, providers of financial assets, or other economic agents are willing to provide to the marketplace.
In microeconomics, supply and demand is an economic model of price determination in a market.
System dynamics (SD) is an approach to understanding the nonlinear behaviour of complex systems over time using stocks, flows, internal feedback loops, table functions and time delays.
Valence, as used in psychology, especially in discussing emotions, means the intrinsic attractiveness/"good"-ness (positive valence) or averseness/"bad"-ness (negative valence) of an event, object, or situation.
In electronics, a voltage divider (also known as a potential divider) is a passive linear circuit that produces an output voltage (Vout) that is a fraction of its input voltage (Vin).
A water clock or clepsydra (Greek κλεψύδρα from κλέπτειν kleptein, 'to steal'; ὕδωρ hydor, 'water') is any timepiece in which time is measured by the regulated flow of liquid into (inflow type) or out from (outflow type) a vessel where the amount is then measured.
A windmill is a mill that converts the energy of wind into rotational energy by means of vanes called sails or blades.
The World Bank (Banque mondiale) is an international financial institution that provides loans to countries of the world for capital projects.
Inverse feedback, Negative Feedback, Negative feedback control system, Negative feedback inhibition, Negative feedback loop, Negative-feedback, Reverse feedback, Servo loop, Single-loop servomechanism.