Browse Prior Art Database

Magnetic Head Driver Circuit

IP.com Disclosure Number: IPCOM000097762D
Original Publication Date: 1961-Jun-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Pingry, CO: AUTHOR

Abstract

A magnetic head driver circuit and a magnetic head having a center tapped winding are combined so as to continually apply erase current flow through one-half of the winding except when a write pulse is applied to the input of the driver. At this time, the erase current is interrupted and write current flows through the other half of the winding.

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Magnetic Head Driver Circuit

A magnetic head driver circuit and a magnetic head having a center tapped winding are combined so as to continually apply erase current flow through one- half of the winding except when a write pulse is applied to the input of the driver. At this time, the erase current is interrupted and write current flows through the other half of the winding.

The driver circuit is essentially a monostable multivibrator. In its stable condition transistor T1 is cut off and transistor T4 conducts passing erase current through erase coil C(e). A negative pulse applied to the input terminal 1 passes through diode 2 to the base 3 of transistor T2.

This transistor current amplifies the pulse and applies it to the base 4 of transistor T1 to establish conduction in this transistor. This produces a positive pulse at its collector which is applied to the base 5 of transistor T3. T3 current amplifies this pulse and applies the amplified pulse to the base 6 of transistor T4 to cut it off and interrupt the erase current. Simultaneously, the write current through coil C(w) is applied since transistor T1 presents a low impedance to ground through resistor R1.

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