attenuátor

An attenuator (Hungarian: attenuátor) is a passive device that reduces the amplitude of a signal without significantly distorting its waveform. In electrical contexts, attenuation is achieved by dissipating part of the signal’s power as heat with a resistor network that presents a defined impedance to both source and load, typically 50 ohms in RF systems.

Electrical attenuators come in fixed and adjustable forms. Fixed units use resistor pads (Pi or T networks) to provide a specified attenuation in decibels. Variable models allow changing attenuation while preserving impedance matching. Attenuators protect receivers, calibrate test equipment, and set signal levels without altering the source.

In audio engineering and general electronics, attenuators lower signal levels to prevent clipping, balance levels between devices, or create appropriate input ranges for meters. They are designed to minimize distortion and noise beyond the intended attenuation, with attention to power handling and frequency response.

Optical attenuators reduce light power in fiber-optic systems, using neutral density filters, fiber-based attenuators, or MEMS devices. Attenuation is expressed in decibels and used to protect photodetectors, manage optical power budgets, or simulate link conditions during testing.

Key design considerations include impedance matching, insertion and return loss, temperature stability, and power handling. Attenuators may be passive or, in some high‑power or wideband cases, require active elements. Selection depends on attenuation, frequency range, and system impedance.