Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
159 words
An electric discharge lamp circuit arrangement comprising: a pair of terminals for connection to an alternating current supply; a ballast impedance comprising a capacitance connected between one of said terminals and one of a pair of main discharge electrodes of the lamp; a connection between the other of said terminals and the other of said main electrodes; heating means for at least one of said main electrodes a controllable switching device connected with the lamp to provide a current path between said pair of terminals comprising, in series, said capacitance, said heating means and said switching device; and a voltage breakdown device connected between the control electrode and a main electrode of said switching device; the voltage breakdown device being a reverse breakdown rectifying device so as to provide a unidirectional current conducting path whereby said capacitance charges from said supply while said switching device is open in a sense such as to bias said breakdown device towards breakdown.
Claim 2
Dependent Claim
159 words
An electric discharge lamp circuit arrangement comprising: a pair of terminals for connection to an alternating current supply; a ballast impedance comprising a capacitance connected between one of said terminals and one of a pair of main discharge electrodes of the lamp; a connection between the other of said terminals and the other of said main electrodes; heating means for at least one of said main electrodes a controllable switching device connected with the lamp to provide a current path between said pair of terminals comprising, in series, said capacitance, said heating means and said switching device; and a voltage breakdown device connected between the control electrode and a main electrode of said switching device; the voltage breakdown device being a reverse breakdown rectifying device so as to provide a unidirectional current conducting path whereby said capacitance charges from said supply while said switching device is open in a sense such as to bias said breakdown device towards breakdown.
Claim 3
Dependent Claim
27 words
A circuit arrangement according to claim 1 wherein said unidirectional conducting path extends through the switching device between its control electrode and one of its main electrodes.
Claim 4
Dependent Claim
45 words
A circuit arrangement according to claim 1 wherein said unidirectional conducting path extends through a rectifier which is connected in series with said voltage breakdown device and which by-passes a path through said switching device between its control electrode and one of its main electrodes.
Claim 5
Dependent Claim
46 words
A circuit arrangement according to claim 3 wherein said voltage breakdown device is connected with the control electrode of the switching device via a resistance connected in parallel with a capacitor and the rectifier is connected to the junction of said resistance and the breakdown device.
Claim 6
Dependent Claim
44 words
A circuit arrangement according to claim 4 wherein said voltage breakdown device is connected to said switching device via two resistances in series, one of which is connected in parallel with a capacitance, and said rectifier is connected to the junction between said resistances.
Claim 7
Dependent Claim
160 words
An electric discharge lamp circuit arrangement comprising: a pair of terminals for connection to an alternating current supply; a ballast impedance comprising a capacitance connected between one of said terminals and one of a pair of main discharge electrodes of the lamp; a connection between the other of said terminals and the other of said main electrodes; heating means for at least one of said main electrodes; a controllable switching device connected with the lamp to provide a current path between said pair of terminals comprising, in series, said capacitance, said heating means and said switching device; a voltage breakdown device connected between the control electrode and a main electrode of said switching device; and a rectifier connected between the main electrodes of the switching device so as to provide a unidirectional conducting path whereby said capacitance charges from said supply while said switching device is open in a sense such as to bias said voltage breakdown device towards breakdown.
Claim 8
Dependent Claim
160 words
An electric discharge lamp circuit arrangement comprising: a pair of terminals for connection to an alternating current supply; a ballast impedance comprising a capacitance connected between one of said terminals and one of a pair of main discharge electrodes of the lamp; a connection between the other of said terminals and the other of said main electrodes; heating means for at least one of said main electrodes; a controllable switching device connected with the lamp to provide a current path between said pair of terminals comprising, in series, said capacitance, said heating means and said switching device; a voltage breakdown device connected between the control electrode and a main electrode of said switching device; and a rectifier connected between the main electrodes of the switching device so as to provide a unidirectional conducting path whereby said capacitance charges from said supply while said switching device is open in a sense such as to bias said voltage breakdown device towards breakdown.
Claim 9
Dependent Claim
37 words
A circuit arrangement according to claim 6 wherein said rectifier is connected in series with a further voltage breakdown device whose breakdown voltage is such that the unidirectional conducting path becomes inoperative when the lamp has struck.
Claim 10
Dependent Claim
24 words
A circuit arrangement according to claim 6 wherein said voltage breakdown device has a breakdown voltage greater than the peak voltage of the supply.
Claim 11
Dependent Claim
20 words
A circuit arrangement according to claim 6 wherein said ballast impedance includes an inductance connected in series with said capacitance.