waterproof circuit boards

[dknguyen]

I'm pretty sure it's just conduction. THen again, there are other components in the phone like the speaker or contacts that coujld be gunked up from getting wet or residues left behind.

 

[srimannarayanakarthik]

I'm pretty sure it's just conduction. THen again, there are other components in the phone like the speaker or contacts that coujld be gunked up from getting wet or residues left behind.

if its just by conduction,cant we use instualed wires that protect the ciruit from moisture.i mean if the wires are covered they will not conuct on coming in contact with water

 

[Nigel Goodwin]

Water is conductive, and quite highly corrosive, if you dry it out completely and VERY quickly after water damage you can often reciver the unit. If left components start to corrode, and it's often more trouble and expense than it's worth!.

SM components tend to far worse than normal ones, water gets underneath and isn't easily removed.

 

[ParkingLotLust]

Technically, pure water isnt conductive, but who has pure water lying around

 

[desperadogear]

water would of course spoil the ics, lcd's, battery and speaker. after all chips are not meant to be used in water.

 

[ParkingLotLust]

You can submurse anything non-mechanical (ICs, resistors, capacitors, etc) in anything non-conductive (Pure Water, deionized) and it will work fine.

 

[Nigel Goodwin]

You can submurse anything non-mechanical (ICs, resistors, capacitors, etc) in anything non-conductive (Pure Water, deionized) and it will work fine.

Pure water is still a solvent though (often called the 'universal' solvent), so it won't stay pure for long - but for flushing a circuit board, followed by heat drying, it's fine.

 

[zevon8]

As soon as the PCB hits the water, the water is contaminated. Materials will disolve or become suspended in the water, altering its characteristics. Current will begin to flow where it shouldn't, and electrolytic and galvanic corrosion will begin very quickly.

 

[ParkingLotLust]

Points well taken. I stand corrected, for the moment at least (insert evil laugh followed by petting of a white cat on my lap here).

 

[dknguyen]

if v are trying to coat a film on a circuit,this may producea lot of heat.how about that.doesnt this effect the efficiecy on the electonic device

That's why you use a thin coat and not big blobs of it. As with epoxy there is probably a very thick coat (like in the case where you want the PCB to be explosion proof) so you can get thermally conductive epoxies to dissipate the heat away.

You don't want to encase your circuit in a brick of silicone.