Engineering Architecture & 360° Optical Emission
The BA7S-4L miniature LED bulb is an engineered drop-in solid-state replacement for traditional BA7S incandescent tungsten indicator lamps (such as Lucas 281, 282, 283, and Osram 3796/3898 series). Designed with an ultra-compact envelope measuring just Φ7.5mm in diameter by 18mm in overall length, it fits seamlessly into the shallowest instrument dial housings, speedometer clusters, tachometers, oil pressure gauges, voltmeters, clock backlights, and industrial control consoles.
Unlike directional forward-firing LEDs that create intense hotspots behind gauge faces, the BA7S-4L deploys 4 precision-mounted SMD 3014 LEDs in a radial perimeter configuration around its compact vertical PCBA tower. This radial layout delivers true 360-degree cylindrical light diffusion, ensuring perfectly uniform, shadow-free backlighting across classic Smiths gauges, vintage automotive clusters, and precision machinery indicator panels.
Precision Dimensional Blueprint (size-Ba7s)
Verify installation clearances using our engineering blueprint below. The standardized 7mm barrel and locking pins replicate factory OEM incandescent bulb envelopes with zero mechanical modification required:
Precision Dimensional Blueprint: Standardized Φ7.0mm bayonet base, Φ7.5mm bulb body, and 18.0mm overall length.
Discrete Voltage Architectures & Versatile Applications
Operating at an ultra-low power consumption of just 0.4W, the BA7S-4L runs at a fraction of the operating temperature of original tungsten bulbs (which frequently melt plastic gauge housings and fade dial print over time). We manufacture discrete voltage variants designed for specific electrical platforms:
- 6VDC Architecture: Direct replacement for vintage European motorcycles (Triumph, BSA, Norton, BMW, Vespa, Lambretta, Moto Guzzi, Ducati), classic mopeds, and 6V antique sports cars.
- 12VDC Architecture: Universal standard for automotive instrument clusters, motorcycle speedometers, marine engine consoles, and flight simulator dials.
- 24VDC Architecture: Heavy-duty commercial trucks, agricultural machinery, military surplus vehicle consoles, and 24V industrial automation switchboards.
- Custom Emitting Colors: In addition to 6500K Cool White, 3000K Warm White, and 4500K Neutral White, we offer factory custom Amber (turn/warning), Red (oil/brake alert), Green (neutral/turn), and Blue (high-beam indicator) options.