Incandescent lamp e.g. H4 lamp, durability improving method for motor vehicle, involves connecting series resistor to spiral-wound filament of lamp in series for predetermined time during switching-on lamp

摘要

The method involves connecting a series resistor (10) e.g. negative temperature co-efficient thermistor (NTC), to a spiral-wound filament (55) of an incandescent lamp in series for a predetermined time during switching-on the lamp. The series resistor is provided with another spiral-wound filament (57), and the predetermined time is long between 5 milliseconds and 100 milliseconds. A third spiral-wound filament is provided in another incandescent lamp, and the NTC is connected in series to spiral-wound filaments (55, 57). An independent claim is also included for a switching arrangement for increasing durability of an incandescent lamp.