Editing Transformer (section)

====Air cores====
A transformer can be produced by placing the windings near each other, an arrangement termed an "air-core" transformer. An air-core transformer eliminates loss due to hysteresis in the core material.<ref name="calvert2001"/> The magnetizing inductance is drastically reduced by the lack of a magnetic core, resulting in large magnetizing currents and losses if used at low frequencies. Air-core transformers are unsuitable for use in power distribution,<ref name="calvert2001"/> but are frequently employed in radio-frequency applications.<ref>{{cite web| first = Reuben| last = Lee| title = Air-Core Transformers| work = Electronic Transformers and Circuits|url=http://www.vias.org/eltransformers/lee_electronic_transformers_07b_22.html | access-date=May 22, 2007}}</ref> Air cores are also used for [[Transformer types#Resonant transformer|resonant transformers]] such as [[tesla coil]]s, where they can achieve reasonably low loss despite the low magnetizing inductance.