Illustrations that help explain electrical charges and magnetic fields.
Illustrations of the “corkscrew rule” (right-hand rule), coils, fields and charges.
Spruyt, Van Mantgem & De Does in Leiden, or ‘SMD Educatieve Uitgevers’ in short, publishes school books for all educational levels.
Jan van Es [design] made hundreds of illustrations for the educational publication ‘Elementaire Elektrotechniek - Elektrische en magnetische velden’ by P.J.G. Ballhaus, A.J.G. Goris and T.J. Kleintjes.