# What happens in a generator so that we get a sinusoidal voltage as an output?

I read this online, " For a travelling magnetic field in a circle, the induced magnetic field in the armature of the generator will be sinusoidal. That's why the generated voltage is a sinusoid, exactly at the same frequency as the generator is turning." I understand that the angular motion is responsible for the sine wave, however, I am very confused about what induces which. I thought magnetic field was either created with a permenant magnet or flow of charge, and that what magnetic field induces was emf, not another magnetic field. Sorry, if these all sound stupid, it all gets confusing after some time, and I don't know where to start.

• Notice they specified the magnetic field is travelling in a circle. Without a diagram I am not sure exactly what it means for the field to be "travelling", but I expect the circular form is critical here. – The Photon Dec 28 '18 at 19:43
• Magnetic fields aren’t induced so either you’ve misquoted the source or the source is unreliable. Voltages or emfs are induced by a changing magnetic field as per Faraday’s law of induction. – Andy aka Dec 28 '18 at 19:43
• Can it be a magnet rotating on its own axis? I have no idea. I was searching about how we get sine wave of voltage with a generator, all got confusing, every source explains it differently, especially this one. – Vyun Dec 28 '18 at 20:32