Inductor-based, step-up switching regulators offer high efficiency, small size and lower cost than isolated switching regulators (DC/DC converters). They are used to amplify (step up) the voltage of a lower voltage source or battery. The inductor stores energy during the on time of the switching transistor and transfers it to the output capacitors and load during the off time. The energy stored in the inductor during the on time is proportional to the inductor and the square of the input current; the energy is then transferred to the load during the off time. If the voltage source or battery is located far away from the switching regulator or its input impedance is high, the PWM in the regulator increases the on time of the switching transistor to compensate for the voltage drop due to the internal impedance of the source or long power connection(s). The negative input resistance of any PWM-based converter demands a low output resistance power source or battery.