Fig. 1 shows an inductor connected to a battery - a constant voltage source. The resistor represents the small residual resistance of the inductor's wire windings. When the switch is closed, the voltage from the battery is applied to the inductor, causing current from the battery's positive terminal to flow down through the inductor and resistor. The increase in current causes a back EMF (voltage) across the inductor due to Faraday's law of induction which opposes the change in current. Since the voltage across the inductor is limited to the battery's voltage of 24 volts, the rate of increase of the current is limited to an initial value of formula_1 So the current through the inductor increases slowly as energy from the battery is stored in the inductor's magnetic field. As the current rises more voltage is dropped across the resistor and less across the inductor, until the current reaches a steady value of formula_2 with all the battery voltage across the resistance and none across the inductance.