Lamp circuit

Claim 2

A lamp testing circuit comprising: a source of electrical energy; a lamp; conducting means connecting said energy source in circuit with said lamp to energize the lamp; another electrical energy source; a dc impedance coupling the output of said another source to the junction of the lamp and its energizing circuit; a sensing circuit; electrical conducting means coupling said sensing circuit to the junction of the lamp and its energizing circuit; and an indicator coupled to said sensing circuit for producing a signal indication when said sensing circuit detects that the lamp is not energized.

Claim 3

The invention as set forth in claim 1 wherein the conducting means coupling the input of said sensing circuit to said junction comprises a diode.

Claim 4

The invention as set forth in claim 1 wherein the another energy source and its associated dc impedance are characterized by being unable to energize the lamp even if it is conductive and being able to energize said sensing circuit only when the lamp is nonconductive.

Claim 5

The invention as set forth in claim 3 wherein the conducting means between the said first-mentioned energy source and the lamp has negligible impedance.

Claim 6

The invention as set forth in claim 3 wherein the conducting means between the said first-mentioned energy source and the lamp comprises a selectively operable on-off switch and a unidirectional conductor in series with the energy source and the lamp.

Claim 7

The invention as set forth in claim 4 wherein said first mentioned energy source is about twice the energy level of the other energy source and the impedance associated with said another energy source is in the order of about one thousand times that of the lamp.

Claim 8

Lamp energizing and testing circuit, comprising: a first energy source; a selectively operable open-close switch, conducting means and a lamp connected in series with said first energy source for energizing the lamp when the switch is closed; a second energy source having an energy level substantially greater than the first energy source; electrical resistance coupling the output of the second energy source to the energizing terminal of the lamp, the impedance of said resistance being such that said second energy source will not energize the lamp; a transistorized circuit capable of being operably switched between conducting and nonconducting conditionS; an indicator connected to the output of said switching circuit for indicating the operating condition of said switching circuit; conducting means coupling the input of said switching circuit to the junction of the lamp and said electrical resistance whereby said switching circuit is caused to operate in one condition when said lamp is nonconductive and in the other condition when the lamp is conductive.

Claim 9

Lamp energizing and testing circuit, comprising: a first energy source; a selectively operable open-close switch, conducting means and a lamp connected in series with said first energy source for energizing the lamp when the switch is closed; a second energy source having an energy level substantially greater than the first energy source; electrical resistance coupling the output of the second energy source to the energizing terminal of the lamp, the impedance of said resistance being such that said second energy source will not energize the lamp; a transistorized circuit capable of being operably switched between conducting and nonconducting conditionS; an indicator connected to the output of said switching circuit for indicating the operating condition of said switching circuit; conducting means coupling the input of said switching circuit to the junction of the lamp and said electrical resistance whereby said switching circuit is caused to operate in one condition when said lamp is nonconductive and in the other condition when the lamp is conductive.

Claim 10

The invention as set forth in claim 7 wherein the conducting means to the input of the switching circuit includes a diode.

Claim 11

The invention as set forth in claim 7 wherein the conducting means in series with the lamp and switch includes a diode.

Claim 12

Lamp energizing and testing circuits, comprising, in combination: a first energy source; a plurality of lamp energizing circuits connected in parallel to said first energy source; each of said lamp energizing circuits comprising, a selectively operable open-close switch, conducting means and a lamp connected in series with the first energy source for energizing the respective lamp when the corresponding respective switch is closed; a second energy source having an energy level substantially greater than the first energy source; a plurality of electrical resistors, each resistor coupling the output of said second energy source to the energizing terminal of a respectively different one of said lamps, the impedance value of each resistor being such that the second energy source will not energize the lamp; a transistorized switch circuit selectively operable in either a conducting or nonconducting condition; an indicator connected to the output of the switch circuit for indicating the operative condition of said circuit; and a plurality of diodes, each diode connected between the input to said switching circuit and a respectively different junction of a resistor and its associated lamp.

Claim 13

Lamp energizing and testing circuits, comprising, in combination: a first energy source; a plurality of lamp energizing circuits connected in parallel to said first energy source; each of said lamp energizing circuits comprising, a selectively operable open-close switch, conducting means and a lamp connected in series with the first energy source for energizing the respective lamp when the corresponding respective switch is closed; a second energy source having an energy level substantially greater than the first energy source; a plurality of electrical resistors, each resistor coupling the output of said second energy source to the energizing terminal of a respectively different one of said lamps, the impedance value of each resistor being such that the second energy source will not energize the lamp; a transistorized switch circuit selectively operable in either a conducting or nonconducting condition; an indicator connected to the output of the switch circuit for indicating the operative condition of said circuit; and a plurality of diodes, each diode connected between the input to said switching circuit and a respectively different junction of a resistor and its associated lamp.

Claim 14

The invention as set forth in claim 10 wherein the conducting means in each lamp energizing circuit includes a diode.

Claim 15

In an automobile electrical circuit in which a lamp is energized by a main energy source through an on-off switch, a circuit for testing the conductivity of the lamp, comprising: a second energy source having an energy level substantially greater than said main energy source; a dc impedance connecting said second energy source to the lamp filament; a sensing circuit electrically coupled to the lamp filament, said sensing circuit being activated by said second energy source when said lamp is nonconductive; and an indicator coupled to said sensing circuit for producing a signal indication when said sensing circuit is activated.

Claim 16

In an automobile electrical circuit in which a lamp is energized by a main energy source through an on-off switch, a circuit for testing the conductivity of the lamp, comprising: a second energy source having an energy level substantially greater than said main energy source; a dc impedance connecting said second energy source to the lamp filament; a sensing circuit electrically coupled to the lamp filament, said sensing circuit being activated by said second energy source when said lamp is nonconductive; and an indicator coupled to said sensing circuit for producing a signal indication when said sensing circuit is activated.

Claim 17

The invention as set forth in claim 12 wherein said second energy source and the dc impedance are such that the second energy source cannot energize the lamp.