Use of semiconductors in heating devices

Se.miconducto.rs are subst.ances that h.ave electro.nic conduct.ivity, whic.h occupies a.n intermed.iate posit.ion betwee.n metals a.nd insulato.rs. They d.iffer from met.als in that t.he carriers o.f electric cu.rrent in t.hem are cre.ated by the.rmal motio.n, light, t.he flow of e.lectrons, etc., a.n energy sou.rce.