Effects of the use of the surface charge theory-based approach to understanding of direct current circuits in university studies University of Joensuu, Finland E-mail: pekka.e.hirvonen@joensuu.fi

Correspondence
Pekka E. Hirvonen
Department of Physics
University of Joensuu
P.O. Box 111
FIN-80101 Joensuu
E-mail: pekka.e.hirvonen@joensuu.fi