u2032 may be determined at different times the result of the relation is the same although the currently measured voltage 11 u2032 is measured at a different time at time 600 u03bcs than the calibration voltage value 11 at time 400 u03bcs moving to fig2 g the complete voltage waveform need not be determined and any calibration voltage value does not have to be set a relation between the currently measured voltage values 12 u2032 and 13 u2032 is determined the at least two currently measured voltage values 12 u2032 13 u2032 in the current pulse are measured at different times of the same pulse the system may determine an incorrect stimulation e g based on knowledge of the correct voltage drop the correct voltage drop may be determined by the system manufacturer operator as an absolute voltage value in volts dependent on a first maximum value or by a ratio of currently measured voltage values with respect to a first maximum value or a percentage of a first maximum value or it may be derived from a mathematical model in an alternative application the magnetic stimulation device may send a notification concerning the hardware error to the service department and or manufacturer to repair the device the magnetic stimulation device may also include a black box for storing data concerning unintended events to provide.