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 gain less than 1.
Attenuators are usually passive devices made from simple voltage divider networks. Switching between different resistances forms adjustable stepped attenuators and continuously adjustable ones using potentiometers.
Fixed attenuators in circuits are used to lower voltage, dissipate power, and to improve impedance matching
Basic circuits used in attenuators are pi pads (π-type) and T pads.