Pulsing circuit including a switching and current regulator circuit

Claim 2

In a telephone system including an exchange having switching means, a plurality of subscriber telephone sets, a telephone line individually connecting each telephone set to the switching means for selecting individual ones of said telephone lines, and a direct current power source, a pulsing circuit comprising: a control device including a coil responsive to be actuated by a current flow therethrough; a current regulator circuit; circuit means connecting said current regulator circuit and said coil in a direct current series circuit between said switching means and said power source so that said switching means can connect said series circuit to a telephone line, wherein the series circuit, a connected telephone line and telephone set define a telephone loop connection and wherein said current regulator circuit conducts to activate said control device in response to a closed circuit condition in the telephone loop connection and controls the amount of current flow through the telephone loop, when closed, within a preset range, and switching control circuit means coupled to said series circuit and said current regulator circuit so that said switching control circuit means detects when said telephone loop is switched from a closed to an open circuit condition and applies a control signal to said current regulator circuit that momentarily cuts off said current regulator circuit.

Claim 3

A telephone system as defined in claim 1 wherein said current regulator circuit is cut off by said control circuit for a period of time on the order of the duration of the open circuit portion of a telephone dialing pulse.

Claim 4

A telephone system as defined in claim 2 wherein said control device is a relay.

Claim 5

A telephone system as defined in claim 2 wherein said control device is a saturable reactor.

Claim 6

In a telephone system including an exchange having switching means, a plurality of subscriber telephone sets, a telephone line individually connecting each telephone set to said switching means for selecting individual ones of said telephone lines, and a direct current power source, a relay pulsing circuit comprising: a relay including a coil; a transformer including a primary winding and a secondary winding; a current regulator circuit including a current regulating transistor wherein the collector and emitter of said transistor define a regulating current path; circuit means connecting the regulating current path of said current regulator circuit, said primary winding and said relay coil in a direct current series circuit between said switching means and said power source for connection across a telephone line; circuit means for applying a forward bias to said current regulating transistor so that said current regulator conducts to energize said relay in response to a closed circuit condition in a connected telephone set and controls the amount of current flow in the series circuit within a preset range, and a control circuit coupled to said current regulating transistor and to said secondary winding for momentarily removing said forward bias when a signal is developed by said secondary winding indicating that a connected telephone set was open circuited.

Claim 7

In a telephone system including an exchange having switching means, a plurality of subscriber telephone sets, a telephone line individually connecting each telephone set to said switching means for selecting individual ones of said telephone lines, and a direct current power source, a relay pulsing circuit comprising: a relay including a coil; a transformer including a primary winding and a secondary winding; a current regulator circuit including a current regulating transistor wherein the collector and emitter of said transistor define a regulating current path; circuit means connecting the regulating current path of said current regulator circuit, said primary winding and said relay coil in a direct current series circuit between said switching means and said power source for connection across a telephone line; circuit means for applying a forward bias to said current regulating transistor so that said current regulator conducts to energize said relay in response to a closed circuit condition in a connected telephone set and controls the amount of current flow in the series circuit within a preset range, and a control circuit coupled to said current regulating transistor and to said secondary winding for momentarily removing said forward bias when a signal is developed by said secondary winding indicating that a connected telephone set was open circuited.

Claim 8

A relay pulsing circuit as defined in claim 5 wherein said control circuit includes: a control transistor; capacitive means coupled to the base and emitter of said control transistor; a rectifying circuit coupled between said capacitive means and said secondary winding, responsive to a preset polarity of signals across said secondary winding for applying a charge across said capacitive means for rendering said control transistor conduCtive, and circuit means for connecting said emitter and collector of said control transistor to said current regulating transistor so that said current regulating transistor is rendered non-conductive when said control circuit transistor is conductive.

Claim 9

A relay pulsing circuit as defined in claim 6 wherein: a second rectifying circuit is coupled between said secondary winding and said capacitive means responsive to a signal across said secondary winding having a polarity opposite said preset polarity for charging the capacitive means in a direction opposite said rectifying circuit responsive to said preset polarity of signals; second capacitive means, and circuit means connecting said second capacitive means to said series circuit so that said second capacitive means stores a charge when said current regulator circuit is conductive and functions to provide a current surge through said primary winding in a direction so that said first mentioned capacitive means renders said control transistor non-conductive when a connected telephone set switches from an open to a closed circuit condition.

Claim 10

A relay pulsing circuit comprising: a pair of conductors for connection to a switching circuit that connects and disconnects a direct current circuit across said pair of conductors; a pair of power terminals for connection to a direct current power source; a relay having a coil; a transformer having a primary winding and a secondary winding; a current regulator circuit; circuit means connecting said primary winding, said relay coil, and the current regulator circuit in a direct current series circuit between said power terminals and said pair of conductors; circuit means connected to said current regulator circuit for applying a signal thereto for controlling the amount of current flow through said series circuit, when said direct current circuit is connected across said conductors within a preset limit; a transistor; circuit means connecting the emitter and collector electrodes of said transistor to said current regulator circuit so that said current regulator circuit is rendered non-conductive when said transistor is conductive; capacitive means; a rectifying circuit coupled between said secondary winding and said capacitive means responsive to a preset polarity of signals across said secondary winding for applying a charge to said capacitive means, and circuit means connecting said capacitive means to the base and emitter electrodes of said transistor so that when the current flow through said series circuit is interrupted a charge is developed by said capacitive means that momentarily renders said transistor conductive.

Claim 11

A relay pulsing circuit comprising: a pair of conductors for connection to a switching circuit that connects and disconnects a direct current circuit across said pair of conductors; a pair of power terminals for connection to a direct current power source; a relay having a coil; a transformer having a primary winding and a secondary winding; a current regulator circuit; circuit means connecting said primary winding, said relay coil, and the current regulator circuit in a direct current series circuit between said power terminals and said pair of conductors; circuit means connected to said current regulator circuit for applying a signal thereto for controlling the amount of current flow through said series circuit, when said direct current circuit is connected across said conductors within a preset limit; a transistor; circuit means connecting the emitter and collector electrodes of said transistor to said current regulator circuit so that said current regulator circuit is rendered non-conductive when said transistor is conductive; capacitive means; a rectifying circuit coupled between said secondary winding and said capacitive means responsive to a preset polarity of signals across said secondary winding for applying a charge to said capacitive means, and circuit means connecting said capacitive means to the base and emitter electrodes of said transistor so that when the current flow through said series circuit is interrupted a charge is developed by said capacitive means that momentarily renders said transistor conductive.

Claim 12

A relay pulsing circuit as defined in claim 8 wherein said current regulator circuit is connected between said relay coil and said power terminals.

Claim 13

A relay pulsing circuit as defined in claim 8 including: a second relay coil magnetically coupled to said other relay coil; a second primary winding magnetically coupled to said other primary winding, and circuit means for connecting said second relay coil and said second primary winding in said series circuit so that a coil and a winding are located in opposite legs of said series circuit to provide a balanced configuration, and so that said second coil and second primary winding are connected in a flux-aiding manner with said other coil and said other primary winding respectively.

Claim 14

A relay pulsing circuit as defined in claim 8 including: a second rectifier circuit coupled between said secondary winding and said capacitive means, responsive to a signal across said secondary winding having a polarity opposite to said preset polarity, for charging said capacitive means in a direction opposite to said other rectifying means to develop a charge across said capacitive means to render said transistor non-conductive; second capacitive means, and circuit means coupling said second capacitive meAns coupled to said series circuit so that said second capacitive means stores a charge when said current regulator circuit is conductive and discharges through said primary winding when said switching circuit is closed providing a current flow in a direction so that said first mentioned capacitive means receives a charge for rendering said transistor non-conductive.

Claim 15

An electrical circuit comprising: a control device having a coil; a current regulator circuit; a pair of power terminals for connection to a direct current power source; a pair of input terminals for connection to a switching circuit for connecting and disconnecting a direct current circuit across said input terminals; circuit means connecting said coil and said current regulator circuit in a direct current series circuit between said power source and said input terminals so that said current regulator circuit conducts to energize said device when a direct current circuit is connected across said pair of input terminals and the current regulator circuit controls the amount of current flow through said series circuit within a preset range, and control circuit means coupled to said series circuit and said current regulator circuit for detecting when an open circuit is exhibited across said pair of input terminals to apply a control signal to said current regulator circuit to momentarily render the current regulator circuit nonconductive.

Claim 16

An electrical circuit comprising: a control device having a coil; a current regulator circuit; a pair of power terminals for connection to a direct current power source; a pair of input terminals for connection to a switching circuit for connecting and disconnecting a direct current circuit across said input terminals; circuit means connecting said coil and said current regulator circuit in a direct current series circuit between said power source and said input terminals so that said current regulator circuit conducts to energize said device when a direct current circuit is connected across said pair of input terminals and the current regulator circuit controls the amount of current flow through said series circuit within a preset range, and control circuit means coupled to said series circuit and said current regulator circuit for detecting when an open circuit is exhibited across said pair of input terminals to apply a control signal to said current regulator circuit to momentarily render the current regulator circuit nonconductive.

Claim 17

An electrical circuit as defined in claim 12 wherein said control circuit means includes: inductive means connected in said series circuit for providing a signal when the current flow through said series circuit is interrupted, and a control circuit coupled to said inductive means and said current regulator circuit for applying said control signal to said current regulator circuit having a controlled time duration in response to the signal from said inductive means.

Claim 18

An electrical circuit as defined in claim 13 wherein said control circuit includes: a control transistor; capacitive means coupled to the base and emitter of said control transistor; a rectifying circuit coupled between said capacitive means and said inductive means for applying a charge across said capacitive means for rendering said control transistor conductive, and circuit means for connecting said control transistor to said current regulator circuit so that said current regulator circuit is rendered non-conductive when said control transistor is conductive.

Claim 19

An electrical circuit as defined in claim 14 wherein: said current regulator circuit includes a transistor having its emitter and collector connected in said series circuit, a resistor in series with the emitter and a biasing circuit for providing a substantially constant forward bias for said transistor, and the emitter and collector of said control transistor is coupled to said biasing circuit for overcoming said forward bias to render the series transistor non-conductive when the control transistor is conductive.

Claim 20

An electrical circuit as defined in claim 12 wherein said control device is a relay.

Claim 21

An electrical circuit as defined in claim 12 wherein: said control device is a saturable reactor, and said control circuit means is coupled to a second coil on said saturable reactor.

Claim 22

A pulsing circuit comprising: a pair of conductors for connection to a switching circuit that connects and disconnects a direct current circuit across said pair of conductors; a pair of power terminals for connection to a direct current power source; a saturable reactor having a pair of coils; a current regulator circuit; circuit means connecting one of said coils and the current regulator circuit in a direct current series circuit between said power terminals and said pair of conductors; circuit means connected to the current regulator circuit for applying a signal thereto for controlling the amount of current flow through said Series circuit, when a direct current circuit is connected across said pair of conductors within a preset range; a transistor; circuit means connecting the emitter and collector electrodes of said transistor to said current regulator circuit so that said current regulator circuit is rendered non-conductive when said transistor is conductive; capacitive means; a rectifying circuit coupled between the other one of said coils and said capacitive means for applying a charge thereto, and circuit means connecting said capacitive means to the base and emitter electrodes of said transistor so that when the current flow through said series circuit is interrupted a charge is developed by said capacitive means that momentarily renders said transistor conductive.

Claim 23

A pulsing circuit comprising: a pair of conductors for connection to a switching circuit that connects and disconnects a direct current circuit across said pair of conductors; a pair of power terminals for connection to a direct current power source; a saturable reactor having a pair of coils; a current regulator circuit; circuit means connecting one of said coils and the current regulator circuit in a direct current series circuit between said power terminals and said pair of conductors; circuit means connected to the current regulator circuit for applying a signal thereto for controlling the amount of current flow through said Series circuit, when a direct current circuit is connected across said pair of conductors within a preset range; a transistor; circuit means connecting the emitter and collector electrodes of said transistor to said current regulator circuit so that said current regulator circuit is rendered non-conductive when said transistor is conductive; capacitive means; a rectifying circuit coupled between the other one of said coils and said capacitive means for applying a charge thereto, and circuit means connecting said capacitive means to the base and emitter electrodes of said transistor so that when the current flow through said series circuit is interrupted a charge is developed by said capacitive means that momentarily renders said transistor conductive.