SMN 6.3-20

Which parameters define its operation?

The lamp produces a restrained 0.26 lm luminous flux. It is therefore intended for a small indicator window or a nearby scale rather than general lighting. The 600-hour reference service life should be considered together with the switching conditions and the voltage available in the actual unit. 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 3.2 mm bulb and special base distinguish this version from the wire-ended SMN 6.3-20-2. The lamp is installed in a matching miniature holder; the base type and available space must therefore be checked before replacement. 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?

Order by the complete designation SMN 6.3-20. A similar voltage marking alone is not enough: the current, base and overall dimensions must match the equipment documentation. If the old lamp has flexible leads, the -2 version may be the relevant item instead. 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.