SMN 10-55

Which parameters define its operation?

The combination of moderate current and 1,500-hour reference life is intended for regular indication rather than a short, high-intensity flash. Correct supply voltage is especially important for stable brightness and predictable life. The electrical rating should be considered together with light output and operating duty. Overvoltage raises filament temperature and will normally shorten service life.

How is the lamp constructed and installed?

The lamp has a 3.2 mm bulb, an overall length of about 9 mm and a special miniature base. It is mechanically distinct from SMN 10-55-2, which is fitted with flexible leads for direct soldering. Before installation, compare bulb diameter, overall clearance and the exact connection method. The lamp must not be forced into an unsuitable holder, loaded through the glass envelope or fitted by changing the original mounting arrangement.

Where is this execution used?

Lamps in this group are used for local indication and illumination inside compact instruments, annunciators and illuminated controls. Installation in a particular aircraft, helicopter, panel or instrument must be confirmed by the applicable parts list or equipment documentation. The SMN or MN family name alone does not establish aircraft applicability.

How should the correct lamp be selected?

Select by the complete SMN 10-55 marking and verify the holder type. Similar-looking miniature lamps can be rated for 9 V or use different currents, so appearance alone is not a safe interchangeability criterion. Related products on the card help compare nearby executions in the same narrow subgroup; they do not establish automatic interchangeability. An enquiry should include the marking of the removed lamp, circuit voltage, holder or lead type and the required quantity.