H7 Bulb vs. W5W / T10 Bulb
Comparing 2 standards across 10 specifications. 10 key differences identified.
The H7 Bulb (standardized under UN ECE Regulation 37 with a PX26d flanged base) is the most widely used single-filament halogen automotive headlight bulb in the world. Operating at 55W nominal at 12V (rated at 13.2V test voltage), it generates 1,500 lumens (±10%) primarily for low-beam projector and reflector headlight assemblies.
The W5W Bulb (commonly called a T10 Wedge or 194 / 168 in North America, standardized under ECE Regulation 37 with a W2.1×9.5d base) is the universal automotive miniature capless glass bulb. Operating at 5W at 12V (generating ~50 lumens), it is the standard for front parking lights, side turn indicators, license plate lamps, and cabin interior courtesy lights.
Specification Comparison Table
10 Parameters| Parameter / Spec | ||
|---|---|---|
|
Standardization
|
UN ECE R37 Category H7 / IEC 60061-1 sheet 7004-5 / US DOT Category H7 | UN ECE R37 Category W5W / US DOT Type 194 / 168 / IEC 60061-1 |
|
Base Socket Designation
|
PX26d (pre-focused metal circular mounting flange with one flat reference indexing tab) | W2.1×9.5d (Capless glass wedge base: 2.1 mm thickness × 9.5 mm width) |
|
Nominal Power & Voltage
|
55 W @ 12V nominal (tested at 13.2V standard regulation voltage; draws ~4.17 A) | 5 W @ 12V (tested at 13.5 V; draws approx. 0.40 A) |
|
Luminous Flux Output
|
1,500 lumens ± 10% (at 13.2 V) | 50 lumens ± 20% (at 13.5 V) |
|
Filament Type
|
Single axial tungsten filament (no internal shield; strictly a single-beam bulb) | — |
|
Average Lifespan (B3 / Tc)
|
B3 (97% survival): ~330 hours | Tc (63.2% failure): ~550 hours (standard halogen) | — |
|
Electrical Terminals
|
2 spade push-on terminals (6.3 mm faston tabs spaced 14.5 mm apart) | — |
|
Bulb Envelope Diameter
|
— | T10 designation indicates tubular glass envelope diameter of 10.0 mm (3/8 in) |
|
Electrical Contact Wires
|
— | Two bare molybdenum lead wires folded across opposite sides of the flattened glass wedge base |
|
Applications
|
— | Front sidelights/eyebrow markers, side fender repeaters, license plate illumination, interior map/dome lights, trunk cargo lamps |