Current transformer current transformers" are also used (usually with an oscilloscope) to measure waveforms of high frequency or pulsed currents within pulsed power systems. Unlike CTs used for power circuitry, wideband CTs are rated in output volts per ampere of primary current. If the burden resistance is much less than inductive impedance of the secondary winding at the measurement frequency then the current in the secondary tracks the primary current and the transformer provides a current output that is proportional to the measured current. On the other hand, if that condition is not true, then the transformer is inductive and gives a
Inductance to the lower voltage end. The energy from the external circuit required to overcome this "potential hill" is being stored in the increased magnetic field around the conductor. Therefore, any inductance with a current through it stores energy in its magnetic field. At any given time formula_21 the power formula_22 flowing into the magnetic field, which is equal to the rate of change of the stored energy formula_23, is the product of the current formula_3 and voltage formula_20 across the conductor From (1) above When there is no current, there is no magnetic field and the stored energy is zero.