exciter

An exciter is a device that provides the initial energy or signal needed to drive a system, initiating a response that can be monitored or controlled. The term is used in several technical contexts with different meanings but a common idea: supplying the stimulus that causes a system to operate or produce output.

In electrical power generation, an exciter supplies the direct current to the rotor field winding of a synchronous generator. By establishing the rotor’s magnetic field, it enables the generator to develop voltage and transfer reactive power. Excitation systems may be brushless, static, or DC-excited. Brushless systems use an auxiliary AC generator and a rotating rectifier; static systems use power electronics to provide controlled DC from a separate source. An automatic voltage regulator modulates the excitation to maintain terminal voltage and system stability.

In audio and signal processing, an exciter is a processor or effect that adds harmonic or high-frequency content to a sound to brighten it or enhance perceived detail. This can involve subtle non-linear processing, spectral shaping, or intentional distortion. Exciters are common in music production, mastering, and some broadcast gear, and they are distinguished from limiters, compressors, or saturators by their specific psychoacoustic goals.

In testing and instrumentation, an exciter is a source that physically stimulates a device or structure. Examples include vibration shakers, impulse hammers, or piezoelectric exciters used to provoke responses for measurement, modal analysis, or quality assurance.