Lighting is an important part of all modern airplanes. A typical airplane has anywhere from hundreds to thousands or even tens of thousands of individual bulbs. Some of them large, such as external navigation lights and anti-collision lights. Miniature and subminiature bulbs, however, are characterized by smaller and more compact.
The Basics of Miniature and Subminiature Bulbs
Miniature and subminiature bulbs are exactly what they sound like: small bulbs that produce light. They are used in applications where a full-size bulb would be too large, too heavy or unnecessarily bright.
Miniature vs Subminiature Bulbs
The terms “miniature” and “subminiature” are often used interchangeably to describe smaller-than-average bulbs. The only difference is that subminiature bulbs are generally smaller than their miniature counterpart.
Miniature bulbs typically range from 5 to 15 millimeters wide. Subminiature bulbs, on the other hand, are often less than 5 millimeters wide.
Common Types of Miniature and Subminiature Bulbs
There are different types of miniature and subminiature bulbs, one of the most common being incandescent. Incandescent bulbs operate on the same principle as ordinary household lightbulbs. They feature a thin metal filament — typically made of tungsten — that releases photons in response to an electrical current. Electricity travels through the filament, resulting in visible light.
There are also LED miniature and subminiature bulbs. They don’t have a filament. Instead, LEDs operate via electroluminescence. They feature a diode that responds to electricity. As electricity travels through the semiconductor-based diode, they release photons.
Why Airplanes Use Miniature and Subminiature Bulbs
Airplanes use miniature and subminiature bulbs for several reasons. Instrument lights, for instance, often consist of these smaller-than-average bulbs. Instrument lights don’t need to flood the entire cockpit with bright light. rather, they just need to illuminate a small and specific spot. Miniature and subminiature bulbs excel at this task without wasting energy.
Regular-sized bulbs can produce too much light for instruments. Not only does this create wasted energy; it can interfere with pilots’ visibility. Pilots must pay close attention to instruments like the airspeed indicator, altimeter, engine gauges and switch labels. If regular-sized bulbs were used to illuminate these instruments, they would produce a bright glare that interferes with pilots’ visibility. Miniature and subminiature bulbs offer a solution by producing a small, focused beam of light.
Another reason airplanes use miniature and subminiature bulbs is for simplicity. They feature a simple design that eliminates the need for complex electronics. Whether incandescent or LED, miniature and subminiature bulbs can be quickly installed. They can also be controlled using basic switches.
