Alarm circuit

Claim 2

A selectively regenerative circuit, which comprises: first and second means for producing a single output pulse after first and second predetermined times, respectively, in response to an input signal; means for applying a first input signal to the first pulse producing means only, in order to actuate the first pulse producing means to produce an output pulse therefrom; an indicator responsive to the output pulse from the first pulse producing means to provide an indication; means for applying a second input signal to both the first and the second pulse producing means in order to actuate the first pulse producing means in order to produce an indication; said second pulse producing means responsive to the coincidence of the output of the first pulse producing means and the second input signal for actuating the second pulse producing means to produce a single output pulse the second predetermined time after the output of the first pulse producing means; and means coupling the output of the second pulse producing means for actuating the first pulse producing means to provide a second output pulse therefrom the first predetermined time after the output of the second pulse producing means, thereby providing repetitive indications.

Claim 3

A circuit as recited in claim 1 wherein the first and second output pulse producing means are first and second monostable multivibrators, the first multivibrator having a trigger input and the second multivibrator having both a trigger input and an enabling input.

Claim 4

A circuit as recited in claim 2, wherein: the first input signal applying means comprises a first input signal line and a gate, the first input signal line providing an input to the gate and the gate providing an input to the trigger input of the first multivibrator; and the second input signal applying means comprises a second input signal line connected to the enable input of the second multivibrator and a capacitor connected between the second input signal line and an input to the gate.

Claim 5

A circuit as recited in claim 3, wherein the means responsive to the output of the first pulse producing means and the second input signal for actuating the second pulse producing means comprises a capacitor connected between the output of the first pulse producing means and the trigger input of the second pulse producing means.

Claim 6

A circuit as recited in claim 4, wherein the means responsive to the output of the second pulse producing means for actuating the first pulse producing means comprises a capacitor connected between the output of the second pulse producing means and an input to the gate.

Claim 7

A circuit as recited in claim 5, wherein the indicator is an audible alarm.

Claim 8

A selectively regenerative circuit, which comprises: first and second monostable multivibrators, each capable of receiving an input signal and generating an output pulse of a predeteRmined length in response thereto, the first multivibrator having a trigger input and the second multivibrator having both a trigger and an enabling input; means for coupling the output of the first multivibrator to the trigger input of the second multivibrator to provide an input thereto to trigger the second multivibrator upon the termination of the output pulse from the first multivibrator; a gate, the output of the gate being connected to the trigger input of the first multivibrator to provide an input thereto; means for coupling the output of the second multivibrator to the gate to provide a first input thereto to trigger the first multivibrator upon the termination of the output pulse from the second multivibrator; an indicator device for receiving output pulses from the first multivibrator and for providing an output in response thereto; first and second input lines, the first input line connected to provide a second input to the gate and the second input line providing an input to the enabling input of the second multivibrator; means for coupling the second input line to the gate to provide a third input thereto; and means for selectively applying an input signal to the first or the second input lines, whereby an input signal on the first input line operating to trigger the first multivibrator to provide a single output from the indicator device, and an input signal on the second input line operating to both trigger the first multivibrator, and to enable the second multivibrator, so that the termination of the output from the first multivibrator operates to trigger the second multivibrator and so that the termination of the output from the second multivibrator operates to trigger the first multivibrator, the first and second multivibrators thereby being alternately triggered to provide a repetitive output from the indicator device in response to the repetitive triggering of the first multivibrator.

Claim 9

A selectively regenerative circuit, which comprises: first and second monostable multivibrators, each capable of receiving an input signal and generating an output pulse of a predeteRmined length in response thereto, the first multivibrator having a trigger input and the second multivibrator having both a trigger and an enabling input; means for coupling the output of the first multivibrator to the trigger input of the second multivibrator to provide an input thereto to trigger the second multivibrator upon the termination of the output pulse from the first multivibrator; a gate, the output of the gate being connected to the trigger input of the first multivibrator to provide an input thereto; means for coupling the output of the second multivibrator to the gate to provide a first input thereto to trigger the first multivibrator upon the termination of the output pulse from the second multivibrator; an indicator device for receiving output pulses from the first multivibrator and for providing an output in response thereto; first and second input lines, the first input line connected to provide a second input to the gate and the second input line providing an input to the enabling input of the second multivibrator; means for coupling the second input line to the gate to provide a third input thereto; and means for selectively applying an input signal to the first or the second input lines, whereby an input signal on the first input line operating to trigger the first multivibrator to provide a single output from the indicator device, and an input signal on the second input line operating to both trigger the first multivibrator, and to enable the second multivibrator, so that the termination of the output from the first multivibrator operates to trigger the second multivibrator and so that the termination of the output from the second multivibrator operates to trigger the first multivibrator, the first and second multivibrators thereby being alternately triggered to provide a repetitive output from the indicator device in response to the repetitive triggering of the first multivibrator.

Claim 10

A circuit as recited in claim 7, wherein at least one of the coupling means comprises a capacitor.

Claim 11

A circuit as recited in claim 8, wherein each coupling means comprises a capacitor.

Claim 12

A circuit as recited in claim 9, wherein the first multivibrator is constantly enabled to provide an output pulse in response to an input signal.

Claim 13

A circuit as recited in claim 10, wherein: the indicator device is an audible alarm device; an amplifier is connected to provide an input to the alarm device in response to an input signal to the amplifier; and the output pulse of the first multivibrator provides an input signal to the amplifier.