Road vehicle lighting system

A road vehicle electrical system including a generator charging a battery, a voltage regulator coupled to and controlling charging of the battery, a lighting switch, a pair of tungsten-halogen lamps having a rated operating voltage range, connected across the battery through said lighting switch, and a pair of regulators respectively connected to one said lamp, each of said pair of regulators maintaining the voltage across its respective lamp within said operating voltage range of the lamp, each latter said regulator including a transistor in series with the lamp said transistor including a base, collector and emitter, and means for switching the transistor on and off to regulate the voltage across the lamp and a resistor connected across the collector-emitter of Road lights the transistor.

Description:

FIELD OF INVENTION

This invention relates to road vehicle lighting systems.

SUMMARY OF INVENTION

A road vehicle lighting system according to the invention includes at least one tungsten-halogen lamp, and a regulator in circuit with the lamp for maintaining the voltage across the lamp within the intended operating voltage range of the lamp.

Preferably, the regulator includes a transistor in series with the lamp, and means for switching the transistor on and off to regulate the voltage across the lamp. Preferably, a resistor is connected across the collector-emitter of the transistor. Advantageously, a delay network is incorporated to hold the transistor off for a period when the lamp is first turned on.

In another aspect, the invention resides in a road vehicle electrical system including a generator charging a battery, a voltage regulator controlling charging of the battery, a pair of tungsten-halogen lamps connected across the battery through a lighting switch, and a pair of regulators, one for each lamp, each of said pair of regulators maintaining the voltage across its lamp within the intended operating voltage range of the lamp.

BRIEF DESCRIPTION OF DRAWING

An example of the invention is illustrated in the accompanying drawings, in which:

FIG. 1 is a block diagram of an electrical system of a road vehicle, and

FIG. 2 illustrates the preferred form of the regulator for each of the lamps shown in FIG. 1.