Detecting Conductive Particles on Magnetic Disks
Original Publication Date: 1986-Dec-01
Included in the Prior Art Database: 2005-Mar-09
For detecting detrimental electrically conductive particles on a magnetic disk, an isolated magnetic head slides at low speed on the magnetic disk and is connected to a voltage source through a holding spring. When the magnetic head encounters an electrically conductive particle, the voltage drops for a short time, generating a measurable pulse. The proposed detection principle is shown in the figure. A grounded magnetic disk 1 moves slowly at about 200 rpm, while an isolated suspended magnetic head 2 slides on it. Spring 3 of magnetic head 2 is connected through resistor R to voltage source 4. Voltage V may be indicated by an oscilloscope 5.