if pure water is not conductive why would condensation be an issue for electronics?
I mean, it should be close to pure water, right? Why would some condensation short electronics?
As others have said, corrosion.
To add to that, condensate is rarely pure water. At least, not by the time it’s chilling on the circuits. It’ll pick up any dust, and other stuff fairly quickly; making it not-pure. And conductive.
The water contributes to rust which is bad for electronics long term
Second, electrolytes on the surface of the electronics, bits of metal, dust, or whatever can enter the water and provide a pathway for electricity.
That's my guess anyway.
It's not pure. It's water from the air, which contains all sorts of crap. Especially if you smoke or have pets.
It’s not pure once it starts dissolving or corroding the metal or other materials.
And, if you can sufficiently dry the item (including inside of things), pure water is not a threat to electronics; it’s often used to clean solder flux.
Causes corrosion.
Causes circuit boards to swell and deform.
Yup, electronics tech here and we have to bake our boards to remove moisture from the mid-layers before conformal coating them. We do boards which go through pretty harsh conditions so moisture trapped in the boards could cause massive issues at sub zero temperature and swelling from evaporating liquids cause issues at high temperatures.
Less of a concern for consumer tech but can be a huge concern at industry levels.
Water dissociates in the presence of electrical voltage into hydrogen and oxygen, and that makes it somewhat conductive (due to ionisation).
The bigger problem however is corrosion. Said oxygen causes corrosion.
Because it is really, really difficult to get pure water. Even distilled water isn't pure. I'm not even sure you can get pure water outside of an industrial or laboratory setting
Not very easy, even then. Very pure water will absorb CO2 out of the air to make carbonates, it will strip ions from the surface of most materials you'd want a make a distillation column from. It's a very aggressive solvent.
If you burn hydrogen and oxygen, you’ll get pure water, but you would need to store it immediately after the reaction. If you let the water sit in a bucket, it’s going to absorb all sorts of things from the air around it.
You rarely encounter pure water out in the world; even rainwater will have things dissolved in it.
Even then, there may be chemicals like solder flux or electrolyte from a leaky capacitor that water might dissolve and become conductive enough to cause problems.
Same reason why they use distilled water in water cooled computers
Because pure water isn't conductive while impure water is
It's the impurities in the water that conducts electricity
"pure water" is not what you think it is. It really doesn't exist outside of laboratory conditions.
Pure water is conductive, especially if you apply electrochemical potential. Look up autodissociation of water.
Condensation isn't pure water.
There are also parts that aren't purely gold, and corrosion damage is a concern too.
Isn't it water that basically turned to vapor and then back? That should get rid of most minerals.
This would require both the air and surface to be free of dust. Maybe in a lab that could be true, but probably not in the real world.
If water vapor was the only thing airborne, then this would be mostly plausible. But the reality in any typical environment is for small particles of dust, soot, microplastics, VOCs, etc to be in the air, in addition to the usual suspects of oxygen, nitrogen, carbon dioxide, etc. Some of those will increase the conductance of water, when condensed upon a cool surface. Think of water vapor as a lint filter that floats around the room until it lands on something.
But even in a hermetically sealed environment with only the typical atmospheric mix of oxygen and nitrogen and other trace elemental gases, and then water vapor, there's still a problem. Air has a conductivity -- measured in Siemens, the inverted unit of Ohms which is resistance -- of 3-8 x 10^-15, meaning it will not conduct much at all. But compared to condensation upon a PCB in this sealed environment, DI water has a conductance of 5.5 x 10^-6. That is 1,000,000,000x times more conductive, although it's still a tiny amount.
The reality is that all circuits and electronics leak small currents here and there, even through the air or through their PCB substrates. But the sum total of these leakage and creepage currents will be negligible in all but high-voltage circuits. Though that's only under the rated environmental conditions.
When air is fully saturated at 100% humidity, some of those currents become noticeable. And for high-voltage switchgear, it can become an issue very quickly. But outright water on most circuits would be disastrous due to arcing or shorting or both, even for low voltage things.
Ok, but it's condensing on something that isn't perfectly clean.
But then things like Whiskey and Gin would not exist....
Going to reply to your comment since it seems relevant but mixing metals in water can also corrode it
It's why you don't mix and match metals in PC water cooling