Attenuator (electronics): Difference between revisions
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*[http://www.amptone.com/powerattenuatorfaq.htm Guitar amp power attenuator FAQ] |
*[http://www.amptone.com/powerattenuatorfaq.htm Guitar amp power attenuator FAQ] |
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*[http://amps.zugster.net/articles/attenuation Basic attenuator circuits] |
*[http://amps.zugster.net/articles/attenuation Basic attenuator circuits] |
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*[http://beradio.com/notebook/passive_attenuators/ Passive Audio Attenuators] |
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[[Category:resistive components]] |
[[Category:resistive components]] |
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Revision as of 18:55, 31 January 2007
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An attenuator is an electronic device that reduces the amplitude or power of a signal without appreciably distorting its waveform. Attenuators are usually passive devices made from resistors. The degree of attenuation may be fixed, continuously adjustable, or incrementally adjustable.
Low level attenuators
An attenuator is effectively the opposite of an amplifier, though the two work by different methods. While an amplifier provides gain, an attenuator provides loss, or negative gain.
A fixed electrical attenuator is often called a pad, especially in telephony and audio engineering. The input and output impedances of an electrical attenuator are usually matched to the impedances of the signal source and load, respectively.
A line-level attenuator in the preamp or a power attenuator after the power amplifier uses electrical resistance to reduce the amplitude of the signal that reaches the speaker, reducing the volume of the output. A line-level attenuator has lower power handling, such as a 1/2-watt potentiometer. A power attenuator has higher power handling, such as 10 or 50 watts.
Power attenuators
In audio electronics, attenuators are used as a dummy load by sending all of the power to the resistor and none to the speaker, in order to silence or reduce the output volume of an audio amplifier (for example, a guitar amplifier). Silencing an amplifier is useful for biasing the positive and negative signal crossover, for running bench tests such as measuring the amplifier's maximum output wattage, and for adding line-level effects between a guitar amplifier and a guitar speaker.
Guitar amplifier attenuators
One of the main purposes of guitar amplifiers is to provide various shades of power-tube distortion. Power attenuators for guitar are used for signal processing to obtain musically useful power-tube distortion at controlled volume levels.