Headlight bulbs

[Fred Kerrick]

What's the difference between 'discharge headlights' and 'halogen headlights'?  Need to replace a headlight.

[RX400h]

Quote

Halogen Headlights¹²:

• Halogen headlights use a tungsten filament inside a bulb. When electric current passes through the filament, it heats up and generates light.
• They differ from regular incandescent bulbs in that they have a dose of halogen gas instead of argon gas. This allows the filament to burn hotter, thus giving off more light.
• Halogen headlights are typically yellowish in color.
• They were the standard for the auto industry for years because they were cheap to manufacture and simple to replace.
• The downside is that halogen bulbs must be made of special glass and handled in such a way that you don’t leave fingerprints on them. These can cause a hot spot on the glass, which can cause the bulb to fail within minutes.

Discharge (HID) Headlights:

• HID headlights use an electric arc between two electrodes and a high-pressure gas (typically xenon) to generate light.
• HID headlights create a much more powerful light - measured in thousands of lumen - for a given amount of wattage used.
• The resultant light created by the plasma is extremely bright and white in color.
• They are more efficient compared to halogen bulbs but also more expensive.

In summary, while halogen headlights are cheaper and simpler, HID headlights are more efficient, brighter, and have a whiter light. However, the design of the headlight assembly and the reflectors also affects performance, along with how well the headlights are aimed¹.