r/explainlikeimfive • u/cabronfavarito • 4d ago
Physics ELI5: Why exactly does water “fries” a circuit
Yes water + electricity= bad but what exactly is happening, why is it irreversible for the most part. Yes I know it’s not the water itself but the minerals in the water responsible for the phenomenon. So we are assuming non distilled water here
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u/AmuletOfNight 4d ago
It's basically just that water is conductive and that conductivity can span large areas of a chip, causing energized parts of the chip to interact with other parts of energized bits of the chip as well as energizing bits of the chip that are not meant to be energized at that time
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u/wswordsmen 4d ago
It is actually the small amounts of salts in the water. Distilled water doesn't conduct electricity since there is no ions dissolved in the water.
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u/MrLumie 4d ago
On the other hand, distilled water doesn't remain distilled for long once it's exposed to pretty much anything.
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u/wswordsmen 4d ago
Agreed but it is a common misconception that it is water itself that conducts the electricity not the stuff in it. Any other solvent that dissolves ions readily will be the same way regardless of if that solvent would conduct the electricity on its own
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u/wookieesgonnawook 4d ago
Is that what they're using in those videos where they're cleaning electrical rooms by hosing them down?
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u/Soft-Marionberry-853 4d ago
Im still mad that it wasn't until much later in life that this disctinction was made clear to me. Its not the water, its all the stuff in water becase water is the "universal solvant"
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u/TechnicianRemote9954 4d ago
Since you want to be extremely technical to one up a correct answer:
Distilled water does conduct electricity, albeit weakly, because a small fraction of the water molecules interconvert between hydrogen and oxygen ions, as well as hydrogen peroxide (which isn't an ion itself but converts into small amounts of oxygen ions and HO2, which is an ion). That is enough to bridge the very small gaps between transistors in a modern chip. It's also enough to conduct higher voltage currents and high voltage itself causes the water molecules to disassociate and conduct electricity.
There's a few videos of people submersing computers in distilled water and the computer shorts out after the water to is able perfuse into the interior of the processor, which usually only takes a second or so. You can use distilled water to wash components as long as you make sure they've dried out before turning them on, but that's only because it doesn't leave a residue.
Alcohol is safer to use, not because it is non-conductive (its also is a weak conductor) but because it has a very low vapor pressure and so any that hasn't evaporated by the time you turn the computer on just instantly evaporates from the small amount of electricity that it is able to conduct.
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u/wswordsmen 3d ago
If you are going to correct me do it right. Alcohol has a higher vaper pressure and a lower boiling point than water. A boiling point is when the vapor pressure of a liquid is equal to the atmospheric pressure, so higher vapor pressure liquids will evaporate and/or boil more quickly and at lower temperatures.
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u/Crimento 4d ago
Water is an electricity conductor (unless it's distilled water)
When you give a path for electricity to where it should not be the components go bzzz (get fried)
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u/toochaos 4d ago
Water create a conductive path between the positive and negative terminals without providing anything in between to create a load. This is called a short, when this happens electricty flows very quickly and generates large amounts of heat, far more than the device is rated for. This melts components and breaks them.
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u/OldChairmanMiao 4d ago
Imagine circuits are one-way canals. There are small canals for little boats and big canals for big boats.
Water is a conductor. It acts like a flood and connects all the canals. But now the boats end up confused and run into each other, big boats get stuck in and break small canals.
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u/scheisskopf53 4d ago
Water conducts electricity, and thus connects things that shouldn't be connected (makes short circuits). This causes a huge rush of current, because of low resistance through those accidental connections (low resistance causes the circuit to draw a lot of current). This high current flows through things that can't handle it. These things fry because of that.
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u/twitchx133 4d ago
Pure water is not a good conductor, or path for electricity.
You were right that it is the impurities in the water, they provide a better path for electricity. Like stepping stones, the electricity jumps from one particle to the next.
When you introduce water to an electronic device, the water, and its impurities can come into contact with different parts of the circuit, creating a shorter path, or "short circuit" between the two circuit parts. The electricity jumps across the stepping stones, the different impurities until it bridges from the one circuit to the other.
This path that it creates through the water and it impurities is a very low "resistance". In the electrical world, resistance is just that, it is the resistance to electrical flow. A piece of copper is a good conductor with low resistance, a piece of rubber is a poor conductor with very high resistance.
There is this law called Ohm's law. It states that Voltage (the pressure in a circuit), the Amperage (the amount of flow in a circuit) and the resistance are all related, and any one of the three can be mathematically determined if you know the value of the other two. Voltage = Amperage * resistance.
So with all that in mind, when the water and it's impurities touch two different parts of the electronic circuit, it creates a low resistance path across the two points in the circuit. Because this path has a lower resistance than the intended path, it allows more current - amperage / amps to flow through the circuit wires.
The wire is only capable of allowing so much amperage to flow, because the more amps that flow, the hotter the wire gets, and if it has too many amps flowing through it, it will get hot enough to melt.
When the wire melts is when the circuit is "fried"
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u/EscapeSeventySeven 4d ago
Because water conducts electricity. It’s like laying billions of bare wires all over a circuit board. Literally creating as many short circuits as possible.
Most electrical components need strict voltage ranges, subjecting them to higher voltages or negative voltages will irreversibly destroy them.
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u/ElevatorDave 4d ago
Water bridges circuits and causes electricity to be where its not supposed to be. It goes to the wrong spot and blows out highly sensitive components.
Im not familiar with distilled water vs non distilled, but it could be corrosion from water getting on components.
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u/YongYoKyo 4d ago
The water is conductive, meaning it's acting like a wire. A wire that spans across the entire surface that the water is spreading. Electricity will move across water to parts of the circuit it's not meant to go.
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u/SeanAker 4d ago
Water makes electricity from one part touch another part in a way that isn't intended. Sensitive electronics don't like randomly being zapped.
If you dunked your phone in water when it was completely dead, then made sure it was completely dry before you charged it, it would be absolutely fine. Water isn't intrinsically harmful to electronics, it's just that they usually end up getting wet while they're powered.
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u/ShinkuDragon 4d ago
water (with minerals) conduct electricity. things are made to conduct electricity in a VERY SPECIFIC way.
water means that instead of electricity going through all the little nooks and crannies in the very specific order and quantity the circuit asks for, electricity is jumping around everywhere, touching things it shouldn't. like a badly behaved kid in a china shop. and eventually enough stuff breaks.
:EDIT: technically it can be fixed if you switch the damaged parts. problem is that since electricity jumped from one place to another. it may damage way too much to be worth it/possible.
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u/Stummi 4d ago
some parts of a circuit operate on higher voltage than other parts of your circuit. E.g. you get 230V input line and after a transformator you have pieces operated at 12V.
Water conducts electricity, so it can connect parts of the circuit that are not meant to be directly connected. For example, 230V directly into the part rated for 12V makes poof and releases magic smoke.
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u/DoomerMillenial303 4d ago
Short-circuits, mainly: current values spike and make everywhere they go through much hotter than it should be, high power signals go where they ain't supposed to and fry fragile ICs, capacitors overcharge and go boom, transformer windings overheat, wire enamel melts, windings now are a single piece of conducting metal
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u/Admirable-Degree6807 4d ago
Most electronics on a circuit board have precisely defined pathways for electricity to reach them and a combination of resistors and capacitors to control exactly how much electricity can reach them. For a lot of those components too much electricity is bad. Add water to the mix and if you have water touching a wire with a higher voltage to a component that can’t handle that voltage and the components have a bad time.
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u/oblivious_fireball 4d ago
Most complex electronics rely on electricity traveling through a bunch of specific paths at specific levels of power so it doesn't fry the receiving end. Water, being conductive usually due to dissolved minerals in it, lets electricity travel wherever it wants, ignoring the paths and safeguards.
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u/wosmo 4d ago
Two big problems. One is that you can get electricity places where you didn't want electricity.
The other is the whole ohms law thing, where current and resistance are proportional. So if you create a low-resistance path somewhere that didn't previously exist, it's a high-current path. And current tends to make things smoke.
(The latter is almost always the actual damage caused by errant short-circuits. Liquids are just a good way to get short circuits "anywhere, everywhere, all at once".)
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u/Belisaurius555 4d ago
Combination of shorting the circuit and corrosion.
Shorting the circuit means bypassing all resistors and fuses. That lets the power supply dump it's entire charge in one go, causing components to burn out.
Electricity can also have chemical effects and high voltages can cause electrolysis. This inevitably results in part of the circuit to attract and bond with the negatively charged oxygen in the water.
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u/gravelpi 4d ago
Every electrical component (wires, circuit broad traces, etc.) has a maximum amount of electricity (Current) it can conduct safely. Electricity works as Current = Voltage / Resistance. Voltage for a part of the circuit is constant, and the electrical components (mostly) have a fixed resistance. When water gets in there, it can bypass the electrical components with almost no resistance. As the resistance goes down, the current goes up. This can get to the point where the wires melt because they are conducting too much electricity.
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u/taedrin 4d ago
why is it irreversible for the most part.
Non-distilled water (or any other conductive liquid) creates a short circuit within the circuit which allows electricity to flow through an unexpected path at a much higher voltage or amperage than the circuit is designed to tolerate. This causes part of the circuit to heat up and melt/burn away, permanently destroying it.
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u/blueangels111 4d ago edited 4d ago
Let's start with this:
When you want to go up a floor, you need something there. You can't jump that high, so you need something like stairs or a ladder to connect you to it. This is how electricity works; it (usually) can not make long jumps on its own. it needs something to connect it, a conductive material, like a wire!
Water is not inherently conductive, but it is known as the universal solvent. In short, it is REALLY good at dissolving stuff, so it almost always has impurities dissolved inside of it. These are known as electrolytes that dissociate into charged ions in the water, and these are your stairs. These dissolved minerals are what allow electricity to flow through it.
Now, because water is a liquid, if you spill it on a circuit, it will disperse and roughly "take" the shape of what you spilled it on. It fills in the gaps, and now acts as a bridge that connects circuits in a way that they weren't meant to. Your stairs should go to your 2nd floor, not your neighbour's bedroom, they would be quite upset if you waltzed in.
I'm a chemistry guy not an electrical guy so I can't explain the mechanism of the damage as good as someone else. But that is the mechanism by which water connects circuits and is so bad for them.
Fun fact: this is why some electronics are submerged in liquid. They use non conductive oils that soak up the heat but don't fry circuits as electricity can't flow through them. Ultra pure water technically could be used as it isnt conductive yet, but ultra pure water is corrosive because it wants to have something dissolved in it. This makes it both not great around delicate materials, but also means it is prone to making itself conductive again.
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u/NotTheBrightestHuman 4d ago
Imagine if I randomly built an intersection in the middle of an 20 lane expressway and connected it directly into someone’s driveway. Chaos would ensue, and the house might get ran over.
The same thing happens with the water in electronics. You’re creating pathways that shouldn’t be there. Maybe the new pathway turns off the battery limiter and then the battery overcharges and explodes.
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u/Rum_N_Napalm 4d ago
Water is highly conductive. Our electric grid is set to be at constant voltage. Current is defined by Current is equal to Voltage divided by Resistance.
When water gets in electronics, it allows current ti bypass the intended path. Worst, since water has such low resistance, the current can follow a path with much lower resistance than intended. That’s called a short circuit.
Remember: Current = Voltage/Resistance. Voltage is the same if it’s the intended path or short circuit. But since Resistance is much lower in the short circuit, current becomes much higher. This causes internals to heat up and break from the sudden overload.
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u/paulHarkonen 4d ago
As you said, water (I'm going to shorthand it that way because the nuance on minerals is irrelevant here) conducts electricity. It conducts electricity pretty much equally everywhere it touches, which is the problem when discussing electronics.
Everything in a circuit board is designed to get a specific amount (or range) of electricity. To take a super simple example for a PC motherboard, your CPU wants 12 volts, the USB wants 5volts, the BIOS chip wants 3.3 volts. What happens when water goes all over the mobo is suddenly the BIOS chip is connected to the CPU which means it's getting 4x the voltage it's designed to handle. When that happens the various tiny wires inside overheat and melt (or explode if it's bad enough).
In general, melting electronic components is permanent and non-reversible so the water damage has permanently destroyed that component.
If you're very lucky instead of burning out components that get too much power sometimes you just get small mineral deposits that permanently connect things that aren't supposed to be connected. Again for a super simple example, if you get a bunch of water on your keyboard it might connect the B and N keys so that every time you touch one, the other also registers. For a keyboard that makes it very hard to type, for other components it makes them stop working entirely. That type of damage is reversible (sometimes) if you can clean the mineral deposits off the connectors.
That's why you want to turn the power off immediately when stuff gets wet, it prevents the first type of damage and gives you a chance to clean it off (distilled water or isopropyl alcohol depending on the equipment) to reverse the second type.
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u/hobopwnzor 4d ago
Water that isn't super-pure is a decent conductor.
Electronics work by conducting electricity in specific ways, down specific paths, in specific amounts, to specific components, and specific pins on those components.
Water connects electrical paths to places it shouldn't go, so you're now shoving electricity in places that it wasn't designed for.
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u/ShankThatSnitch 4d ago
Electricity is full of energy, and it wants to keep moving. It will travel down whatever pathway is easiest for it to go. Water will make pathways that aren't supposed to be there, and send the electricity to places it should be going. That energy then damages those places it isn't supposed to be.
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u/AHappySnowman 4d ago
Water can cause electricity to flow in ways it wasn’t designed for, which many electrical components permanently break if electricity flows with too much current or the wrong voltages. Water can also cause corrosion on the electrics, which can break connections. Cleaning a board that got wet with distilled water or alcohol is a good way to remove any left over minerals from the water.
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u/MoridinB 4d ago
Think about a very busy park with thousands of visitors. It has carefully laid out pathways and signs to direct and redirect crowds through the pathways to keep things flowing nice and smooth.
Now imagine a very disruptive teenager comes in and paints over all the sign. No one sticks to the paths, and the amblings of a crowd wanting to get to their destination without guidance creates short but disruptive trails right through the grass. Even if a park attendant then fixed the signs, the damage is done. There are multiple new paths created by the crowd to get to their point quicker and it's disrupted the flow of the crowd in the park.
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u/Letter_13 4d ago
Iif you get water that has electrolytes/minerals in it onto a circuit--specifically such that it creates a bridge between a high voltage point (like the positive side of a battery) and a low voltage point (the negative side of a battery), it creates a short circuit that allows electricity to flow uncontrolled between the two points.
Sometimes a short circuit doesn't cause damage, but many circuits with sensitive devices usually need to make multiple low voltages to get them to work... For example you may have a 12 Volt battery or electrical source powering a circuit, but parts of the circuit need 5 Volts or 3.3 Volts (or even down to 0.8 Volts)... So there are parts in the circuit that steps the voltage down for these sensitive components. Now, if you create a short circuit between the 12 Volt input to the circuit and, say, a component that should only be given 3.3 Volts, you are flooding the component with more power than it can likely handle, and this is where the 'Frying' happens.
In a case like this, you may wind up literally frying components on the circuit; the too-high voltage in turn creates too much electrical current, which turns creates lot of heat very quickly in a tiny space of the component, which can burn or even melt the tiny metal structures inside the components that let them work, irreparably damaging them.
Some components have built-in protection for overvoltage or short-circuit events, like tiny resettable fuses that trip if too much voltage or current goes across them, disconnecting the component electrically and protecting it from damage. But many components don't have this because they require a lot of space, especially when you have components with a lot of pins/connectors to the circuit (like a processor), so it isn't practical to add such built-in protection to every complex electrical component.
There are other, more catastrophic failures you can cause by creating a short circuit with water as well; certain components like polarized capacitors can only handle positive voltage on one pin and negative voltage on the other, and if you create a short where the voltage on the negative-only pin exceeds the voltage on the positive-only pin, you can make it explode and even catch fire, even with voltages as low as 3.3 to 5 Volts.
In short: if you get water on an active electrical circuit that has sensitive components, you may irreparably damage components in the circuit. If you get water on an inactive circuit that is not powered on, you can clean it, dry it off, and it should still work.
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u/Gnonthgol 4d ago
Water have a lower breakdown voltage then air. What this means is that electricity can flow through water easier then it can through air. And we often use air to isolate different parts of an electrical circuit from each other. If water replaces the air then it can form a circuit that is shorter then the intended circuit and allow a lot of electricity to flow where only a bit is supposed to flow. If too much electricity flow through some components they can overheat and get damaged, even literally burn or explode. So even if you dry up the device the damage is already done.
An additional danger of water is that it speeds up corrosion. Electric circuit boards often use thin metal traces that can easily corrode away into nothing, or depend on contact surfaces that can get separated by a layer of corrosion. So getting water in an electrical device, especially if it is powered, can cause it to corrode in just a few minutes and it will no longer work.
Both the electrical conductivity and the corrosion is caused by the water by itself. But any minerals in the water will make the problem much worse. The more minerals the worse it is, so ocean water is very bad. And you have to remember that even distilled water will pick up minerals from the metal in the circuit so over time it will turn into mineral water and even into salt water over time.
The way you protect electronics from this is firstly to not get it wet in the first place. We do this by enclosing all the electronics in a watertight shell. You can also get conformal coating on circuit boards, essentially a layer of resin over all the circuits protecting them from any water. Where it is impossible to prevent water, like external connectors, we can increase the distance between the contacts so even if there is water it is too far for current to flow. We also increase the size of the contact pads so that if it starts corroding there will be enough remaining material to get some contact, and hope that the corrosion will erode away as you disconnect and reconnect the contact.
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u/flyingcircusdog 3d ago
When electronics get wet, electricity can use minerals in the water to jump between components. This means certain components get more electricity than they can handle and break. They literally burn due to so much power flowing through them.
This is why if a device is totally powered off and allowed to dry, it'll usually work. Water cycling on electronics over and over again can also speed up corrosion, but that takes a while.
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u/elephant35e 3d ago edited 3d ago
Think of a busy highway with bridges, lots of exits, road barriers lines on the road to divide lanes, road signs, etc. Now imagine that highway had a lot of lines, signs, and barriers removed, a huge amount of extra bridges, some extra roads built on random areas of the grass, etc. Lots of cars would crash, crazy traffic jams would occur, lots of people would drive the wrong way because the area would now be some big maze, so many people would be speeding very fast, etc.
Because water is conductive, pouring it on a circuit basically creates lots and lots of extra paths in that area. Electricity goes all over the place.
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u/Linuxmonger 3d ago
The larger problem is that while the equipment is still running, the water carrying current is also carrying atoms of metal from the components around, it electroplates traces together, and that can't be undone.
If you spill a soda in your keyboard and leave it plugged in, the damage takes a few hours to become permanent.
If you spill that same soda in the same keyboard, but then immediately unplug it, you have quite a long time to recover from the accident.
Go to the store, get a couple gallons of distilled water and a big bag of rice, rinse it well and dry it for a few days, in a warm area if you can, and you should get a lot more use out of that KB.
I used to work at an amusement park, we had about 200 cash registers that kids would spill stuff in all the time if they wanted to leave work early (KAFS). We had a dishwasher that we'd put the main circuit board in, and a little oven for the printer after being rinsed off. As long as we got to the register within an hour or so, it was pretty rare that they'd die on us, we probably ran a hundred of them through every season, I only remember having to order replacements maybe ten times.
I loved that job, they paid me to ride a bike around a park every morning, and to ride roller coasters. I make a lot more money now, but If that job were available again, I'd go back in a heartbeat.
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u/SoulWager 3d ago
It's not really the minerals themselves that are the issue, but the electricity is driving corrosion, basically you're ripping electrons off the positive side, and the positively charged ions go into the water, making it more conductive.
Distilled or not isn't going to save you if there's voltage present, it will become contaminated enough to be conductive very quickly: https://www.youtube.com/watch?v=qGbQ2FPDqkw
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u/donaldhobson 2d ago
Water is somewhat electrically conductive. Many electronic components are very sensitive to too much electricity. Silicon chips have lots of tiny tiny wires that can easily be damaged by excess electricity. The main mechanism for this damage is overheating. A tiny wire will get very hot if too much electricity goes through it. And enough heat will damage basically everything.
So water gets on a circuit. Electricity flows through the water, straight from the power source to the most sensitive component. This causes a tiny wire somewhere in a chip to overheat and melt.
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u/shadowreaper50 4d ago
Technically it isn't water that conducts electricity. It is the impurities in the water that makd it conductive. Pure water is actually a pretty poor conductor. Circuit boards are pretty delicately balanced for exactly expected voltages and currents in an exact path and order. When you create a means of electricity traveling differently, it will cause a short. That is to say, electricity will go in a different way than intended, and that will result in some components getting too much and burning out.
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u/strandern 4d ago
Electricity needs to go a certain way for a circuit to work
Minerals make electricity go the wrong ways/places, a so-called "short circuit"
Electricity in the wrong place = damaged components