Control circuit for electromagnetic transducer
First Claim
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1. A circuit for driving an electromagnetic transducer comprising:
- a. a transistor having base, collector and emitter electrodes;
b. a direct current potential source;
c. an electromagnetic transducer having first and second inductively coupled coils for producing opposing and unequal magnetomotive forces in response to a flow of direct current from said direct current potential source through said coils;
d. said first coil being in a circuit between one terminal of said potential source and said collector electrode and said second coil being in a circuit between the other terminal of said potential source and said emitter electrode;
e. first bias means for coupling a control potential derived from said potential source to said base electrode for biasing said base to a predetermined potential; and
f. second bias means including inductive action between said first and second coils for biasing said transistor.
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Abstract
An electronic circuit including a transistor which is biased to conduction is provided to initiate actuation of an electromagnetic transducer. The transducer has first and second coils one of which actuates the sounder. A potential is induced in the other coil and this induced potential is used to cut off the transistor. The next cycle of operation is initiated when the induced potential falls below a predetermined value in response to the reduction of the magnetic flux which, in turn, was the result of the transistor having been cut off.
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Citations
7 Claims
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1. A circuit for driving an electromagnetic transducer comprising:
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a. a transistor having base, collector and emitter electrodes; b. a direct current potential source; c. an electromagnetic transducer having first and second inductively coupled coils for producing opposing and unequal magnetomotive forces in response to a flow of direct current from said direct current potential source through said coils; d. said first coil being in a circuit between one terminal of said potential source and said collector electrode and said second coil being in a circuit between the other terminal of said potential source and said emitter electrode; e. first bias means for coupling a control potential derived from said potential source to said base electrode for biasing said base to a predetermined potential; and f. second bias means including inductive action between said first and second coils for biasing said transistor. - View Dependent Claims (2, 3, 4)
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5. An electromagnetic transducer having a driving circuit comprising:
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a. first and second windings on a common magnetic core coupled in a series circuit and in a sense for inducing a potential in said second winding which is in opposition to the potential across said first winding when a current flows in said series circuit; b. said first winding having a number of turns which is significantly greater than the number of turns of said second winding; c. a potential source coupled to said series circuit for producing a flow of current in said series circuit; and d. potential sensing means coupled to said series circuit to sense when the potential across said second winding exceeds a predetermined value and for terminating the flow of current in said series circuit in response to the potential across said second coil exceeding said predetermined value. - View Dependent Claims (6, 7)
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Specification