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Browse Prior Art Database

MOTORIZED MICROFORM READER

IP.com Disclosure Number: IPCOM000023006D
Original Publication Date: 1976-Jun-30
Included in the Prior Art Database: 2004-Mar-27
Document File: 2 page(s) / 286K

Publishing Venue

Xerox Disclosure Journal

Abstract

Disclosed is a circuit used for controlling the speed of a drive motor in a microform reader, The circuit arrangement is utilized for controlling both the speed and direction of rotation of a small permanent magnet which is used in the described application for driving a reel on a microform reader. A mechanical switch arrangement is provided for enabling the operator to select any one of four operating conditions as well as a fifth off~switchposition,

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XEROX DISCLOSURE JOURNAL

MOTORIZED MICROFORM READER Proposed Classification
R. Fouser U.S. CL 318/3
mt. Cl, H02k 7/14

Disclosed is a circuit used for controlling the speed of a
drive motor in a microform reader, The circuit arrangement
is utilized for controlling both the speed and direction of
rotation of a small permanent magnet which is used in the
described application for driving a reel on a microform
reader. A mechanical switch arrangement is provided for
enabling the operator to select any one of four operating
conditions as well as a fifth off~switchposition,

The electronic transistorized circuit arrangment comprises
an NPN power transistor having a relatively low resistor
impedance coupled between the collector electrode and posi~
tive potential of the power supply and an emitter electrode
which is coupled in series with the armature of the motor.
This emitter coupling can be varied by the mechanical switch
means referred to above, A second transistor comprising a
PNP transistor is provided and the collector electrode of
this second transistor is coupled to the base electrode of
the first transistor, The emitter electrode of the second
transistor is returned to the positive terminal of the power
supply while the base electrode is coupled through a resis~-
tive impedance to the collector electrode of the first tran-~
sistor, These transistors are thus functioning as back~to~
back transistors, each having its collector coupled to the
base of the other transistor, A voltage divide...