Damping is any effect, either deliberately engendered or inherent to a system, that tends to reduce the amplitude of oscillations of an oscillatory system.
In real oscillators friction, or damping, slows the motion of the system. In many vibrating systems the frictional force Ff can be modeled as being proportional to the velocity v of the object: Ff = -cv, where c is the viscous damping coefficient, given in units of newton-seconds per meter.
Similar damped oscillator behavior occurs for a diverse range of disciplines that include control engineering, mechanical engineering and electrical engineering. The physical quantity that is oscillating varies greatly, and could be the swaying of a tall building in the wind, the speed of an electric motor, or the current through a RLC circuit. Generally, damped harmonic oscillators satisfy:
Damping ratio
In engineering, the damping ratio is a measure of describing how oscillations in a system die down after a disturbance. Many systems exhibit oscillatory behavior when they are disturbed from their position of static equilibrium. A mass suspended from a spring, for example, will, if pulled and released, bounce up and down. On each bounce, the system is trying to return to its equilibrium position, but overshoots it. Frictional losses damp the system and cause the oscillations to gradually decay in amplitude towards zero. The damping ratio is a measure of describing how rapidly the oscillations decay from one bounce to the next.
The behaviour of oscillating systems is often of interest in a diverse range of disciplines that include control engineering, mechanical engineering and electrical engineering. The physical quantity that is oscillating varies greatly, and could be the swaying of a tall building in the wind, or the speed of an electric motor, but a normalised, or non-dimensionalised approach can be convenient in describing common aspects of behavior.
Deformation
Deformation can refer to:
Deformation (engineering), a change in the shape or size of an object due to an applied force
Deformation (mechanics), the change in shape and/or size of a continuum body after it undergoes a displacement
Deformation (meteorology), important in the formation of atmospheric fronts
Deformation theory, in mathematics
Deformity, in medicine, a major difference in the shape of body part or organ compared to the average shape of that part
Digital electronics
Digital electronics are electronics systems that use digital signals. Digital electronics are representations of Boolean algebra (also see truth tables) and are used in computers, mobile phones, and other consumer products. In a digital circuit, a signal is represented in discrete states or logic levels. The advantages of digital techniques stem from the fact it is easier to get an electronic device to switch into one of a number of known states, than to accurately reproduce a continuous range of values, traditionally only two states, '1' and '0' are used though digital systems are not limited to this.
Digital electronics or any digital circuit are usually made from large assemblies of logic gates, simple electronic representations of Boolean logic functions.
To most electronic engineers, the terms "digital circuit", "digital system" and "logic" are interchangeable in the context of digital circuits
Displacement current
In electromagnetism, displacement current is a quantity that is defined in terms of the rate of change of electric displacement field. Displacement current has the units of electric current and it has an associated magnetic field.
The idea was conceived by Maxwell in his 1861 paper On Physical Lines of Force in connection with the displacement of electric particles in a dielectric medium. Maxwell added displacement current to the electric current term in Ampère's Circuital Law.
In his 1865 paper A Dynamical Theory of the Electromagnetic Field Maxwell used this amended version of Ampère's Circuital Law to derive the electromagnetic wave equation. This derivation is now generally accepted as an historical landmark in physics by virtue of uniting electricity, magnetism and optics into one single unified theory.
Displacement current applies not only to material media, but to free space as well.
Diode
In electronics, a diode is a two-terminal device (thermionic diodes may also have one or two ancillary terminals for a heater).
Diodes have two active electrodes between which the signal of interest may flow, and most are used for their unidirectional electric current property. The varicap diode is used as an electrically adjustable capacitor.
The unidirectionality most diodes exhibit is sometimes generically called the rectifying property. The most common function of a diode is to allow an electric current in one direction (called the forward biased condition) and to block the current in the opposite direction (the reverse biased condition). Thus, the diode can be thought of as an electronic version of a check valve.
Real diodes do not display such a perfect on-off directionality but have a more complex non-linear electrical characteristic, which depends on the particular type of diode technology. Diodes also have many other functions in which they are not designed to operate in this on-off manner.
Early diodes included “cat’s whisker” crystals and vacuum tube devices (also called thermionic valves). Today the most common diodes are made from semiconductor materials such as silicon or germanium.
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