The “International System” unit of magnetic flux, weber is equal to the flux that produces in a circuit of one turn of wire an electromotive force of one volt, when the flux is uniformly reduced to zero within one second. It is named after the German physicist, Wilhelm Edwuard Weber (1804-1891). The weber was introduced as a practical electromagnetic unit at the International Electrotechnical Commission in Paris in 1933, but it was not much used until the meter-kilogram-second system was generally adopted. The fluxivity of magnetized energy on recording tape is commonly measured in nano-webers per meter. Radiation from transformers and coils can also be rated in webers.