Emergency lighting system using dim to bright flashing operation

Claim 2

A circuit for operating at least one gaseous discharge lamp during both normal and emergency conditions comprising: input means for connecting the circuit to a first source of power providing operating voltage during normal conditions when the first power source is operative; a first oscillator connected to said input means for applying voltage to the lamp at a predetermined frequency thereby to yield a single light level; means for automatically connecting a second source of power to said first oscillator when the first power source is inoperative for providing operating voltage for said first oscillator during emergency conditions; and means for cyclically varying the frequency of said first oscillator in a predetermined range during emergency conditions such that the light level of the lamp varies cyclically.

Claim 3

The circuit as set forth in claim 1 further including: a ballast impedance connected to the at least one lamp and coupled to said first oscillator whereby the impedance of said ballast impedance varies in a predetermined relationship with the frequency of said first oscillator. pg,15

Claim 4

The circuit as set forth in claim 2 wherein said first oscillator includes: a transformer having at least one primary winding, a secondary winding, and a tuning winding, said tuning winding being coupled to said primary and secondary windings and further connected to said first oscillator frequency varying means for varying the frequency of said first oscillator between a first rate and a second rate during emergency conditions.

Claim 5

The circuit as set forth in claim 3 further including: a first switch connected to the second source of power and arranged to autOmatically turn on when the first power source is inoperative; a second switch connected to said tuning winding; a second oscillator connected between said first switch and said second switch, said second oscillator being initiated by the turning on of said first switch; said second switch being turned on at time intervals determined by the frequency of said second oscillator.

Claim 6

The circuit as set forth in claim 3 wherein said ballast impedance includes a ballast capacitance means, said ballast capacitance means being connected to said secondary winding of said transformer.

Claim 7

The circuit as set forth in claim 4 further including: a first tuning capacitance connected to said tuning winding, said first tuning capacitance being in part determinitive of the frequency of said first oscillator during normal conditions and for a first time portion during emergency conditions; a second tuning capacitance connected to said tuning winding and to said second switch, said second capacitance being switched into a circuit relationship with said first oscillator upon the turning on of said second switch, said second tuning capacitance being in part determinitive of the frequency of said first oscillator for a second time portion during emergency conditions.

Claim 8

A circuit for operating at least one gaseous discharge lamp during both normal and emergency conditions, said circuit comprising: input means for connecting the circuit to a source of power for energizing the circuit during normal conditions; connection means for connecting the circuit to a battery for energizing the circuit during emergency conditions when the power source is inoperative; charging means connected to said input means for charging the battery during normal conditions; an inverter-oscillator coupled to said input means and to said connection means for applying operating voltage to the lamp to yield a single light level during normal conditions and a cyclically varying light level during emergency conditions, said inverter-oscillator including a transformer having first and second primary windings, a secondary winding, and a tuning winding, the windings being magnetically coupled together; a first transistor switch having its emitter connected to the battery and arranged to be automatically switched into conduction during the emergency conditions; a programmable unijunction transistor having an anode terminal, a cathode terminal, and a gate terminal, said anode terminal being connected to the collector of said first transistor switch, said gate terminal being connected to the battery; a first capacitance means, one side thereof connected between said collector of said first transistor switch and said anode of said programmable unijunction transistor, for discharging said first capacitance through said programmable unijunction transistor at a predetermined frequency; a second transistor switch having its base connected to said cathode terminal of said programmable unijunction transistor, said second transistor switch responsive to pulses from said programmable unijunction transistor to be turned on; a third transistor switch having its base connected to the emitter of said second transistor switch, said third transistor switch being turned on during each discharge of said first capacitance means and in response to the turning on of said second transistor switch for supplying current to said tuning winding; a full wave rectifier connected betwen the collector and emitter of said third transistor switch for providing bilateral conduction thereof; means for cyclically varying the frequency of said inverter-oscillator in a predetermined range including a second capacitance means connected between said full wave rectifier and said tuning winding for substantially affecting the frequency of said inverter-oscillator when said third transistor switch conducts, and a third capacitance means connected across said tuning winding for substantially affecting the frequency of said inverter-oscillator when said third transistor switch is non-conductive; a ballast capacitance means connected to said transformer secondary winding, the impedance of said ballast capacitance means varying as the frequency of said inverter-oscillator varies for varying the light level of the lamp during emergency conditions.

Claim 9

A circuit for operating at least one gaseous discharge lamp during both normal and emergency conditions, said circuit comprising: input means for connecting the circuit to a source of power for energizing the circuit during normal conditions; connection means for connecting the circuit to a battery for energizing the circuit during emergency conditions when the power source is inoperative; charging means connected to said input means for charging the battery during normal conditions; an inverter-oscillator coupled to said input means and to said connection means for applying operating voltage to the lamp to yield a single light level during normal conditions and a cyclically varying light level during emergency conditions, said inverter-oscillator including a transformer having first and second primary windings, a secondary winding, and a tuning winding, the windings being magnetically coupled together; a first transistor switch having its emitter connected to the battery and arranged to be automatically switched into conduction during the emergency conditions; a programmable unijunction transistor having an anode terminal, a cathode terminal, and a gate terminal, said anode terminal being connected to the collector of said first transistor switch, said gate terminal being connected to the battery; a first capacitance means, one side thereof connected between said collector of said first transistor switch and said anode of said programmable unijunction transistor, for discharging said first capacitance through said programmable unijunction transistor at a predetermined frequency; a second transistor switch having its base connected to said cathode terminal of said programmable unijunction transistor, said second transistor switch responsive to pulses from said programmable unijunction transistor to be turned on; a third transistor switch having its base connected to the emitter of said second transistor switch, said third transistor switch being turned on during each discharge of said first capacitance means and in response to the turning on of said second transistor switch for supplying current to said tuning winding; a full wave rectifier connected betwen the collector and emitter of said third transistor switch for providing bilateral conduction thereof; means for cyclically varying the frequency of said inverter-oscillator in a predetermined range including a second capacitance means connected between said full wave rectifier and said tuning winding for substantially affecting the frequency of said inverter-oscillator when said third transistor switch conducts, and a third capacitance means connected across said tuning winding for substantially affecting the frequency of said inverter-oscillator when said third transistor switch is non-conductive; a ballast capacitance means connected to said transformer secondary winding, the impedance of said ballast capacitance means varying as the frequency of said inverter-oscillator varies for varying the light level of the lamp during emergency conditions.