Stimulation of excitable tissue with time varying magnetic fields

The induced eddy-current waveform that causes stimulation of excitable tissue is proportional to the derivative of the current in the excitation coil; this in turn depends on the damping coefficient (D) in the discharge circuit. The induced current waveform is polyphasic when D is less than 1.0; it is biphasic when D is equal to or greater than 1.0. The duration of the induced current pulse is an important factor in determining the threshold current for stimulation. The relationship between these factors is presented.<>