The efficiency of an entity (a device, component, or system) in electronics and electrical engineering is defined as useful power output divided by the total electrical power consumed (a fractional expression). Look up device in Wiktionary, the free dictionary. ... An electronic component is a basic electronic building block packaged in a discrete form with two or more connecting leads or metallic pads. ... System (from the Latin (systēma), and this from the Greek (sustēma)) is an assemblage of entity/objects, real or abstract, comprising a whole with each and every component/element interacting or related to another one. ... The field of electronics comprises the study and use of systems that operate by controlling the flow of electrons (or other charge carriers) in devices such as thermionic valves (vacuum tubes) and semiconductors. ... Electrical Engineers design power systems… … and complex electronic circuits. ... In arithmetic, a vulgar fraction (or common fraction) consists of one integer divided by a non-zero integer. ... An expression in the very basic sense is the noun form of the verb express. ...

Efficiency of typical electrical devices

Efficiency should not be confused with effectiveness: a system that wastes most of its input power but produces exactly what it is meant to is effective but not efficient. The term "efficiency" only makes sense in reference to the wanted effect. So a light bulb might have 2% efficacy at emitting light yet still be 98% efficient at heating a room. (In practice it is nearly 100% efficient at heating a room because the light energy will also be converted to heat eventually, apart from the small fraction that leaves through the windows). An electronic amplifier that delivers 10 watts RMS of power to its load (for example a loudspeaker), while drawing 20 watts of power from a power source is 50% efficient. (10/20 × 100% = 50%) Effectiveness means the capability of, or success in, achieving a given goal. ... The light bulb is one of the most significant inventions in the history of the human race, illuminating the darkness of the evening and bringing light indoors at all times in order focus on the task at hand. ... In general, efficacy is the ability to produce an effect, usually a specifically desired effect. ... The term amplifier as used in this article can mean either a circuit (or stage) using a single active device or a complete system such as a packaged audio hi-fi amplifier. ... In mathematics, the root mean square or rms is a statistical measure of the magnitude of a varying quantity. ... Closeup of a loudspeaker driver Wall-mounted loudspeaker. ...

• Electric kettle: over 90% (comparatively little heat energy is lost during the 2 to 3 minutes a kettle takes to boil water).

Efficiency of lighting lamps

• Incandescent light bulb: about 10% (15% for halogen lamps).
• Fluorescent light bulb: 30% to 40% (depending on the exact type).
• Light-emitting diode (LED) About 25% (depending on the type, and changing with rapidly developing technology).

High efficiency is obviously desirable when we wish to design systems that can operate from batteries. Inefficiency has a cost (either paid to the power company or the cost of the required power supply) to be weighed against the cost of attaining greater efficiency (choosing different components or redesigning the system). Also, any difference in the input and output power probably produces heat within the system (though noise and other mechanical vibrations involve at least theoretically separate inefficiencies), and that heat must be removed from the system if it is to remain within its operating temperature range. The references in this article would be clearer with a different and/or consistent style of citation, footnoting or external linking. ... The incandescent light bulb uses a glowing wire filament heated to white-hot by electrical resistance, to generate light (a process known as thermal radiation). ... A compact fluorescent lamp A fluorescent lamp is a type of electric lamp that excites argon and mercury vapor to create luminescence. ... Blue, green and red LEDs. ... Design, usually considered in the context of the applied arts, engineering, architecture, and other such creative endeavours, is used as both a noun and a verb. ... System (from the Latin (systēma), and this from the Greek (sustēma)) is an assemblage of entity/objects, real or abstract, comprising a whole with each and every component/element interacting or related to another one. ... This article or section does not cite its references or sources. ... A wall wart style variable DC power supply with its cover removed. ... In common use the word noise means unwanted sound or noise pollution. ... Oscillation is the periodic variation, typically in time, of some measure as seen, for example, in a swinging pendulum. ... [[Image:Translational motion. ...

See also

• Negawatt power
• Battery
• List of electronics topics
• Electronic amplifier
• Thermal efficiency
• Mechanical efficiency

This article may be too technical for most readers to understand. ... This article or section does not cite its references or sources. ... This is a list of communications, computers, electronic circuits, fiberoptics, microelectronics, medical electronics, reliablity, and semiconductors. ... The term amplifier as used in this article can mean either a circuit (or stage) using a single active device or a complete system such as a packaged audio hi-fi amplifier. ... The thermal efficiency of a heat engine is the efficiency in which the chemical energy of a fuel is turned into useful work, though it is also used as a synonym for thermodynamic efficiency. ... In physics, mechanical efficiency is the effectiveness of a machine and is defined as Efficiency is often indicated by a percentage, the efficiency of an ideal machine is 100%. Due to the fact that energy cannot emerge from nothing and the Second law of thermodynamics which states that the quality...

External links

• Conversion: Energy efficiency in percent of passive loudspeakers to sensitivity in dB per Watt and meter