'The ends A and B of a potentiometer wire are connected a driving circuit consisting of a strong battery, a plug key and a rheostat. The driving circuit sends a constant current i through the wire AB.' Can anybody please explain me as clearly as possible what is meant by driving circuit and how does it send a constant current through the wire....... Please.......... I have read that battery creates a potential difference between the two ends and the free electrons in the wire more in a direction opposite to the field created by the p.d. Is it true ???