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Circuit for Selecting Noncenter Tapped Heads in Disk Files

IP.com Disclosure Number: IPCOM000074645D
Original Publication Date: 1971-May-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Walton, CA: AUTHOR

Abstract

A head selection circuit system includes a pair of bipolar transistors Q1, Q2 associated with each head. One of the transistor pair favors conduction in one direction, while the other favors conduction in the other direction. Both transistors are turned on for selection of the head, and thus allows write and read currents to flow, in either direction. The other side of the head circuit is connected to a common bus 10, which may be coupled to ground. To operate the transistor pair that determines head selection, base current is caused to flow continuously during the period of selection. The drive signal to the selected head is controlled by time shared circuits connected to the collectors and emitters of the selection transistors.

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Circuit for Selecting Noncenter Tapped Heads in Disk Files

A head selection circuit system includes a pair of bipolar transistors Q1, Q2 associated with each head. One of the transistor pair favors conduction in one direction, while the other favors conduction in the other direction. Both transistors are turned on for selection of the head, and thus allows write and read currents to flow, in either direction. The other side of the head circuit is connected to a common bus 10, which may be coupled to ground. To operate the transistor pair that determines head selection, base current is caused to flow continuously during the period of selection. The drive signal to the selected head is controlled by time shared circuits connected to the collectors and emitters of the selection transistors. Advantages over prior devices are that less turns are needed on the head and that no center tap is needed.

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