So here we have a diagram, I'm searching a simple circuit. It consists of a switch here. There's a resistor here and there's a simple battery on this side. The circuit is... The circuit is... ...energized by closing the switch. Current flows around the circuit from positive to negative. The increasing current causes a magnetic field to increase. The increasing magnetic field causes a greater number of flux lines to go through the center of the circuit. The increasing number of flux lines going through the center of the circuit by virtue of lensi's law. Induces a back EMF that creates an electric field to oppose the increasing number of flux lines. And so we get this classic development of a back EMF which opposes the original EMF. And so the circuit tries to turn itself off. We say when the switch is closed the source current increases with time. The magnetic flux through the current circuit loop due to this increase current also increases in time. This increasing flux creates an induced EMF. The EMF is known as a sense that creates a current loop that creates a magnetic field that opposes the change in magnetic flux. So the source EMF is apporged by the induced EMF and the current increases gradually. This is called self inductance. The induced EMF is sometimes called a back EMF.