Editing Magnetic amplifier (section)

==Limitations==
The gain available from a single stage is limited and low compared to electronic amplifiers. Frequency response of a high-gain amplifier is limited to about one-tenth the excitation frequency, although this is often mitigated by exciting magnetic amplifiers with currents at higher than [[utility frequency]].<ref name=Westman68/> Solid-state electronic amplifiers can be more compact and efficient than magnetic amplifiers. The bias and feedback windings are not unilateral and may couple energy back from the controlled circuit into the control circuit. This complicates the design of multistage amplifiers when compared with electronic devices.<ref name=Westman68/>

[[File:MagAmp1.jpg|thumb|left|Magnetic amplifier output waveform (violet) at about 50% saturation.  Input (yellow) is 120 VAC 60 Hz.]] [[File:MagAmp4.jpg|left|thumb|Magnetic amplifier output waveform frequency spectrum]]Magnetic amplifiers introduce substantial harmonic distortion to the output waveform consisting entirely of the odd harmonics.  Unlike the [[silicon controlled rectifier]]s or [[TRIAC]]s which replaced them, the magnitude of these harmonics decreases rapidly with frequency so interference with nearby electronic devices such as radio receivers is uncommon.