Abstract: A magnetic head slider including a central pad that is disposed at the trailing edge of the slider and designed to increase the flying height of the slider in response to heat induced protrusion of the head elements. The central pad of the present invention includes a body portion and two arm portions which project forwardly from a leading edge of the body portion, such that the leading portion of the central pad is formed with a generally U-shaped profile. The length of the arm members is preferably from approximately ¼ of the total length of the central pad to approximately ¾ of the total length of the central pad.

Abstract: Based on the measurement of the increase of sinusoidal voltage ?V=Vmaxsine(2?ft) on adding a sinusoidal current ?I=Imaxsine(2?ft+?) to the battery current, where f is the frequency and Imax, the amplitude of the superimposed current, with whose magnitudes the electrochemical impedance of the battery Z(f)=Vmax/Imaxej? is calculated, comprising the application of a first sinusoidal signal of prefixed frequency to the battery which generates an alternate voltage component superimposed over the direct one; eliminating the direct component of the response signal; applying a second periodic voltage signal with a frequency identical to that of said first signal and carrying out a synchronous detection of the alternate component generated by the application of said first signal to obtain the voltage proportional to the electrochemical impedance and evaluate the state of health and charge of the battery.