Charge induction on GMR recording heads caused by AC power fields

A new charge induction mechanism on a head gimbal assembly (HGA) is discussed. According to the dynamic charge induction experiments, there is 30-50 pC of charge induced on the HGA base plate by a small displacement (speed about 10 cm/s) in the 50 Hz AC power fields emanating from the AC charged plate (100 V-rms). During the manufacturing and testing processes, a chance of AC induced ESD could result due to metal-metal contacts between the base plate and the other static charge free objects under a normal ESD control environment.