Electronics protection from condensation 1

[meylaerts]

How do manufacturers of aircraft electronic instruments protect the electronic components from condensation when aircraft descents rapidly from high altitude to ground?

 

[rmetzger]

Inside the aircraft its pressurized and temperature controlled so I doubt it comes into play.

 

[analogkid2digitalman]

Sometimes a conformal coating is applied to PWA's to protect components/traces/solder pads against moisture, contaminants, and mechanical vibration.

Wheels within wheels / In a spiral array
A pattern so grand / And complex
Time after time / We lose sight of the way
Our causes can't see / Their effects.

 

[Warpspeed]

In some electronic systems a resistive heating element can be installed. This may be able to maintain the internal temperature above the dew point so condensation cannot occur. I have seen those gold coloured, finned aluminium cased wire wound power resistors bolted to the inside of the instrument, and connected to the mains supply used in this way.

This additional internal heating may sometimes only be required while the equipment itself is powered down in some instances. The main on/off switch can energize the heating resistor in the off position.

I know nothing of aircraft systems, but have seen heaters used in underground mine electronic equipment, and marine applications where cold and damp are problematic.

The other solution is a hermetic enclosure and a silica gel pouch, some military equipment is like that.

 

[uWaveFDL]

Humiseal spray may have been used also.

 

[MikeHalloran]

The conformal coating that's applied to prevent corona discharge at reduced pressure is also somewhat effective against condensation.



Mike Halloran
NOT speaking for
DeAngelo Marine Exhaust Inc.
Ft. Lauderdale, FL, USA

 

[Instruite]

I am working in Automotive Electonics and We dont use normal Industrial electronics component for Automotive because of severe conditions in case of automobile Like temperature in engine room, etc. the electronic parts are specified differently and all electronic components manufacturer dont supply automotive electronic parts
I guess same applies for the electronic component use in aircraft also.

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[Daltondix]

I design cockpit display electrical systems for military aircraft and in all cases, conformal coating is used to protect the components from moisture, but creating a truly moisture-proof situation is accomplished mechanically. It's an art, really. Gaskets or membranes or a combination of both are used when designing the housing around the circuit. If you're going to rely on conformal coating only, I highly recommend using Parylene coating instead of hand-applied UV coatings or the like because the coating is applied in a gaseous state in a chamber, so it gets in between even the smallest pitch devices and is only a few mils (thousandths of an inch) thick.