Editing Electric generator (section)

====Homopolar generator====
{{main|Homopolar generator}}
A homopolar generator is a [[Direct current|DC]] [[electrical generator]] comprising an electrically conductive disc or cylinder rotating in a plane perpendicular to a uniform static magnetic field. A potential difference is created between the center of the disc and the rim (or ends of the cylinder), the [[electrical polarity]] depending on the direction of rotation and the orientation of the field.

It is also known as a '''unipolar generator''', '''acyclic generator''', '''disk dynamo''', or '''Faraday disc'''. The voltage is typically low, on the order of a few volts in the case of small demonstration models, but large research generators can produce hundreds of volts, and some systems have multiple generators in series to produce an even larger voltage.<ref>Losty, H.H.W & Lewis, D.L. (1973) "Homopolar Machines". Philosophical Transactions for the Royal Society of London. Series A, Mathematical and Physical Sciences. 275 (1248), 69–75</ref> They are unusual in that they can produce tremendous electric current, some more than a million [[amperes]], because the homopolar generator can be made to have very low internal resistance.