Attenuators

An attenuator is a two port electronic device that is used in circuits to lower the amplitude of a specific signal without creating significant distortion in the output. Whereas amplifiers are mostly used to increase gain, attenuators are employed when there is a need to reduce/attenuate the amplitude of a signal and typically have a gain <1 V/V. Attenuators filter noise in circuits by suppressing the unwanted waveforms. In electronic networks, attenuators are usually inserted between the load and the source.
Attenuators can be categorized using various parameters that include: operating frequency input power, maximum conversion loss, operating temperature range and packaging. These parameters must be considered when choosing an attenuator for a specific application. Apart from the parametric approach, attenuators can also be broadly categorized into the following classes: digitally programmable, fixed-value and continuously variable.
Attenuators are widely employed in communications, transmission lines, and radio applications to suppress a strong source signal into a more desirable level to connect to a load. Apart from lowering the power input to desired levels, they also improve impedance matching and reduce noise. To prevent undesirable frequency discrimination, attenuators are designed using non-inductive resistances. Passive attenuators contain voltage divider networks as the building blocks, while active types have integrated circuits and transistors.