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In direct current (DC) circuits, this product is equal to the real power, measured in watts. [3] The volt-ampere is dimensionally equivalent to the watt: in SI units, 1 V⋅A = 1 W. VA rating is most used for generators and transformers, and other power handling equipment, where loads may be reactive (inductive or capacitive).
For most audio applications more power is needed at low frequencies. This requires a high-power amplifier for low frequencies (e.g., 200 watts for 20–200 Hz band), lower power amplifier for the midrange (e.g., 50 watts for 200 to 1000 Hz), and even less the high end (e.g. 5 watts for 1000–20000 Hz).
For reference, about 10,000 100-watt lightbulbs or 5,000 computer systems would be needed to draw 1 MW. Also, 1 MW is approximately 1360 horsepower. Modern high-power diesel-electric locomotives typically have a peak power of 3–5 MW, while a typical modern nuclear power plant produces on the order of 500–2000 MW peak output.
Power ratings are usually given in watts for real power and volt-amperes for apparent power, although for devices intended for use in large power systems, both may be given in a per-unit system. Cables are usually rated by giving their maximum voltage and their ampacity . [ 4 ]
Toasters typically draw 2 to 10 amps at 110 to 260 volts consuming around 600 to 1200 watts of power. Power systems deliver energy to loads that perform a function. These loads range from household appliances to industrial machinery. Most loads expect a certain voltage and, for alternating current devices, a certain frequency and number of phases.
The ampere is named for French physicist and mathematician André-Marie Ampère (1775–1836), who studied electromagnetism and laid the foundation of electrodynamics.In recognition of Ampère's contributions to the creation of modern electrical science, an international convention, signed at the 1881 International Exposition of Electricity, established the ampere as a standard unit of ...
The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m 2 ⋅s −3. [ 1 ] [ 2 ] [ 3 ] It is used to quantify the rate of energy transfer .
Audio stereo power amplifier made by McIntosh The internal view of a Mission Cyrus One hi-fi integrated audio amplifier (1984) [1]. An audio power amplifier (or power amp) amplifies low-power electronic audio signals, such as the signal from a radio receiver or an electric guitar pickup, to a level that is high enough for driving loudspeakers or headphones.