Abstract: A pivot bearing 13 includes: a shaft 21; and a plurality of ball bearings 20 which are arranged in an axial direction with respect to the shaft 21 and each of which has an inner ring 27 fixed to the shaft 21 and an outer ring 25 fixed to a fixing hole 18 of an arm 16 via a tolerance ring 12, the pivot bearing being configured to swing around the shaft. The number of balls of each ball bearing 20 and the number of concave portions of the tolerance ring 12, which are configured to press the outer ring 25, are relatively prime to each other. Accordingly, it is possible to inexpensively make the reliable pivot bearing that achieves high precision with a simple structure, and thus a reliable high density magnetic recording apparatus is provided.

Abstract: A pivot bearing 13 includes: a shaft 21; and a plurality of ball bearings 20 which are arranged in an axial direction with respect to the shaft 21 and each of which has an inner ring 27 fixed to the shaft 21 and an outer ring 25 fixed to a fixing hole 18 of an arm 16 via a tolerance ring 12, the pivot bearing being configured to swing around the shaft. The number of balls of each ball bearing 20 and the number of concave portions of the tolerance ring 12, which are configured to press the outer ring 25, are relatively prime to each other. Accordingly, it is possible to inexpensively make the reliable pivot bearing that achieves high precision with a simple structure, and thus a reliable high density magnetic recording apparatus is provided.

Abstract: A floating driver circuit. A power supply is connected through a signal source to an amplifier's input terminal. The power supply is also connected to a pair of power supply terminals of the amplifier, via at least one resistor for each power supply terminal, so that direct current flows from the power supply into the power supply terminals. Further, at least one capacitor is connected to each power supply terminal. A cable, preferably coaxial, has first and second conductors. The first conductor is connected to a signal output terminal of the amplifier. The second conductor is connected to the power supply terminals through the capacitors. A pair of these circuits is combined at opposite ends of an electrical component to enable measurement of the impedances thereof.