Dobbelfilamentpærer

Dobbelfilamentpærer, also known as dual-filament bulbs, are a type of incandescent light bulb that contains two separate filaments within a single glass envelope. Each filament is designed to produce light at a different wattage or brightness level. This allows for two distinct light outputs from a single bulb, often offering a low-intensity and a high-intensity option.

The primary application for dobbelfilamentpærer is in automotive lighting, particularly for taillights, brake lights, and turn signals. In these applications, one filament serves as the running light (low intensity) and the other as the brake light (high intensity). When the brakes are applied, the higher wattage filament is activated, creating a brighter light that signals to other drivers. Similarly, in turn signal applications, one filament might be for the steady running light while the other is for the flashing signal.

The construction typically involves two tungsten filaments, each connected to separate electrical contacts on the bulb base. By altering the voltage supplied to these contacts, either one or both filaments can be illuminated, thereby controlling the overall light output. The glass envelope is usually clear to allow for maximum light transmission. While effective, dobbelfilamentpærer are being phased out in many automotive applications in favor of LED technology, which offers greater durability, energy efficiency, and longevity. However, they remain in use in older vehicles and some specialized lighting fixtures.