What Are Those Hieroglyphics On Your Laptop Charger?

Look on the back of your laptop charger and you’ll find a mess of symbols and numbers. We’d bet you’ve looked at them before and gleaned little or no understanding from what they’re telling you.

These symbols are as complicated as the label on the tag of your shirt that have never taught you anything about doing laundry. They’re the marks of standardization and bureaucracy, and dozens of countries basking in the glow of money made from issuing certificates.

The switching power supply is the foundation of many household electronics — obviously not just laptops — and thus they’re a necessity worldwide. If you can make a power supply that’s certified in most countries, your market is enormous and you only have to make a single device, possibly with an interchangeable AC cord for different plug types. And of course, symbols that have meaning in just about any jurisdiction.

In short, these symbols tell you everything important about your power supply. Here’s what they mean.

It’s All About Market Access

How did every power supply end up plastered with hieroglyphics? It works like this; Acme Corp wants to sell a Thingamajig in Benchoffistan, so the company sends a pallet of Thingamajigs there. The Customs officer in Benchoffistan looks at this pile of goods and says “how will I know this thing is safe for my citizens to use? You must have appropriate certificates that say this product is allowed to be imported.” And just like that, an industry called “Market Access” is born.

Market Access deals with all kinds of problems: logistics, politics, taxes and tariffs, labels and user manuals, materials, timing, and even occasionally palm greasing. Every country has their own nuances, and there are some companies who specialize in helping negotiate this minefield. Russia requires special testing if a device uses encryption or connects to telecommunications equipment (BLE and WiFi both count). Many countries require in-country testing. Most require an in-country representative of the company to handle filings and communication. Some have lead times in the months.


The first thing you’ll see on every power supply is the Input and Output. The input is almost always “100-240V~50-60Hz. The world runs power to outlets in this range. It means that as an input, the plug expects to be connected to that range of input voltage and frequency. The United States uses 120V/60Hz, Europe uses 230V/50Hz, so it’s nice that the input has a range within all of the countries.

The output line has three pieces of information: the output voltage (typically 5V, 9V, 12V), a solid line over a dashed line indicating DC or a ~ indicating AC, and a current rating, usually in hundreds of milli-amps for smaller blocks that plug in, and amps for supplies where the brick is separate from the plug. When replacing a power supply, you’ll want to match the output voltage, match the AC/DC output, and the output amperage must be at least as big as the previous supply and it can be bigger. That number is just the maximum the supply is rated for, not how much it will deliver.

The next piece is the polarity. This looks like a circle with a + in it, a circle with a – in it, and a C in the center. Almost always, the – will point to the C and the + will point to a dot inside the C. This means that the plug has – (ground) on the outside and positive voltage on the inside. Some older plugs don’t conform to this, so you should always check before you uses a supply.

Generic Use

The house symbol means it’s meant for indoor use only, and the square inside a square means that the mains electricity is double insulated. The X through the garbage can means it should not be disposed of normally but instead recycled with other electronics.

Who Certified Your Power Supply?

There a few big companies that do the testing that have their own icons. It lends validity to the rest of the symbols if you can call up these companies and verify from a single source if they really do have each certificate.

You’ll most often see the UL symbol. UL is Underwriters Laboratories, which is a safety organization. They have a barrage of standard tests that they will run against the device to make sure that it is safe. In most cases, a UL certificate isn’t required for sale, but if your house burns down and it’s because of a non-UL listed supply blowing up, then the insurance company is going to put up a fight because you weren’t using safe equipment in your home. Many large retailers will require that your device be listed as well, since they don’t want to deal with any potential recalls or lawsuits from bad products. Next to each UL symbol should be a license number.

This is a good point to mention that many of these marks may be fake — I’ve run into that when sourcing USB power supplies for a product. Customs agents are going to see the symbol and may not follow up to see if the appropriate certificate actually applies to that product, so it’s not uncommon to look up a UL listing number and see pictures of a similar product. There’s some sort of balance, then, when investigating a product’s certificates. You want to see relevant certs and make sure they are legitimate, but you can’t check everything you touch.

What Countries Have Tested This Power Supply?

The rest of the symbols are going to be country specific, and there are a lot of countries with strange requirements for testing. Power supplies are one thing, but adding intentional radio emissions, like a WiFi or Bluetooth product, steps it up to a whole new level of testing and certifications that are beyond the scope of this article.

In general, the more certificates you see on a product, the less sketchy it is, and the bigger the company manufacturing the product. Small manufacturers aren’t going to have the money or interest to pursue a lot of certifications, and may be flying under the radar on a lot of their sales. It’s also an indicator that the product doesn’t change frequently, and that they’ve locked down their assembly line. You won’t see the manufacturer removing critical components to shave costs at the expense of safety.

93 thoughts on “What Are Those Hieroglyphics On Your Laptop Charger?

    1. From Wikipedia:

      “A logo very similar to CE marking has been alleged to stand for China Export because some Chinese manufacturers apply it to their products. However, the European Commission says that this is a misconception. The matter was raised at the European Parliament in 2008. The Commission responded that it was unaware of the existence of any “Chinese Export” mark”

      1. “They’re the marks of standardization and bureaucracy, and dozens of countries basking in the glow of money made from issuing certificates.”

        Or just what companies stamp on their chargers when they are trying to clone legitimate AC to DC power supplies and pass them off as name brand or official products. There’s been a number of in depth teardown articles here about how the quality of some of those is amazingly suspect and that’s being generous. Some probably are not half bad though but it’s difficult to tell for sure.

        Does eBay still basically turn a blind eye to this? They were so eager to open up subsidized “free” shipping from (mostly) China to drive revenue growth that they have let in a whole host of total junk products, these type of power supplies included. Even basic cables and other electronics are surprisingly not only frequently totally counterfeit but many times what the sellers actually send you is actually physically different from the actual photos.

        Then they ask you to ship it back for a refund. Wait, what?

    2. China Export is a myth, but the fake CE mark is something you will find everywhere, sometimes the spacing is wrong as instead of using the official mark they simply use a home mad copy.

      1. And then other times, like the HP charger in the picture, they use weird spacing even though it is a legit mark, “for whatever reason.” Maybe an intern had to change one of the icons and they weren’t sure about the details. And nobody cared.

        I find myself being suspicious whenever the marks look wrong, but many of the legit marks are slightly wrong, and many of the fake marks are perfectly reproduced. It is good in the general case to look for things being slightly “off,” but here it is maybe not useful in practice.

        1. Spelling errors are a clear giveaway, and more often than not, the Chinese counterfeiters are too retarded to correctly copy the text on the original product. I’ve never understood that; it’s not hard, there are only 26 letters, all easily distinguishable, and it’s just a few words.

    3. Trends in miniaturisation mean that a lot of companies simply compress the CE markings to make space on the product. Plus the Chinese aren’t too bad in getting the spacing right either.

    4. “China export” is a joke that someone told and a bunch of people didn’t get, and keep repeating as if it were reasonable. Like the bagpipe, which is still fooling the Scots to this day.

      The non-conforming CE marks: maybe it’s on purpose, maybe it’s a mistake. Since the CE mark is the manufacturer’s decalaration of conformity, it’s hardly worth “forging” anyway. If you want to put it on your product (and you can stomach the legal liability) you can.

      Anyway, like Van Halen’s M&Ms, companies that don’t even bother getting the spacing right are probably not checking the fine points of electrical safety.

      1. Yes, it is joke name for the symbols used to fool importers or just put on because it looks like everyone does it. That doesn’t mean it isn’t real. I have had shipments of hundreds of PSU’s confiscated and destroyed by U.S. Customs before we figured out the problem. That is pretty real.

        1. There might be more to it than that.

          A company I used to work for years ago was having shipments seized by US customs, but only when they went through a specific airport AND when it included a package for a specific consignee.

          It stopped after we had a solicitor (lawyer for you American chaps) contact the US Embassy about the matter. No explanation was ever given. Just a formal ‘This matter has now been resolved’ letter.

          This was before the current ‘All foreigners are terrorists’ nonsense of course. Now the US Embassy would probably just tell them to piss off :)

        2. The agents set up the purchases and check certs, etc. And they are people we know and visit. Still, not a guarantee. It is not unheard of watch a container go onto a ship yet arrive with scrap metal instead of the construction crane you bought. For big stuff like large laser cutters, we have someone inspect the crating and shipping.

    5. It’s also good to know that CE Mark does not mean that someone tested the device to conform with european norms but that producer or importer promises that it is compliant. In practice many cheap products found not only on street markets but also in big malls have this mark and it means nothing. In case of any problems there will be no responsible people.

    6. I thought ” NOM ” has something to do with the Zombie Attack and it is ok to use during the Zombie Attack. But anyway, thank you for clarifing the icons and symbols. This details helped me understood very clearly. However, I do not trust the Chinese made products that looks like American made.

  1. “They’re the marks of standardization and bureaucracy, and dozens of countries basking in the glow of money made from issuing certificates”

    I’m reading that as “someone else, probably the evil government, is getting rich from keeping me safe”.

    That’s a typical American way of thinking, and that’s why we never get anything nice.

    1. Not quite. I’m American, so I suppose you should consider that bias. Most countries are now requiring that you test LOCALLY to get certified, even though physics look pretty much the same at this scale all over the world. Even if you perform and pass the test, you cannot get certified unless it’s done on their soil. Nationalism isn’t just an American institution, ya know.

        1. Addendum: That doesn’t mean each country could not have a list of trusted other countries for such things, to streamline stuff and reduce cost and overhead.
          Problem then though is that it’s hard to check if a certificate is faked if the registry is in other people’s country, especially if visually the product looks the same. If it’s in your own hands you can also check the trail that lead to the one asking the certificate and their export to your country and the serial number range and all such things to see if it all matches up.

      1. It should be easy to understand, each country has its own Courts and they mostly only are looking at the local laws. The local court doesn’t want to get into evaluating foreign rules, circumstances, laws, etc.

        Understanding of the whole field should flow from the word “Underwriters” in Underwriters Laboratories. That means “insurance company,” and indeed UL is basically an industry trade group owned by the insurance companies.

        So the rules and testing standards are written by insurance companies. And so the context of the rules is not anything abstract about safety, but instead it is about legal liability for safety. That liability is different in each country, and even where the rules and standards are the same the local Court only wants to see the local evidence, because it is what is under their jurisdiction.

        It is as simple as that; different countries have different civil courts, and so they require testing to happen in different places. Local places.

    2. The problem is that safety requirements tend to always increase and never decrease. This means they inevitably pass by the sweet spot and become a nuisance and limits development and progress.

      Obviously, there are various stakeholders that actually do profit from increasing requirements and that simply have safety as a business model, without caring much about actual safety itself. It’s also hard to argue against safety, so these parties generally win any discussion.

      In some countries there are stupid amounts of requirements when it comes to products that really aren’t that complicated or dangerous. Other products which pose a similar amount of danger to the user sometimes have a lot less stringent requirements.

      1. I am not disagreeing with you but where is the sweet spot exactly? It differs significantly depending on the product in question. Plus with all of the exemptions and such in place, they sometimes have little to no actual meaning. Even RoHS items can still contain a fair amount of cadmium, lead and mercury. Medical devices were even exempt in the original directive! There’s only ten things that RoHS restricts!


        Don’t get me started on things like lead in plumbing and how even in schools (and many other buildings) across the USA, it is still a fairly significant issue today (The Flint water crisis is a total disaster as just one recent noteworthy example).

        Nobody really wants to rip out exiting infrastructure and redo it all (except those paid to do so), even if the lead content was allowed to be literally 8% in plumbing used for food and water use and there are considerable numbers of facilities that continue to be grandfathered in or exempted that are legally not required to do anything about it. Sure, there’s probably worse things to deal with but it’s emblematic of the difficulties that one faces when dealing with trying to enact widespread and expensive standards, particularly ex post facto ones or ones that are legitimately very disruptive to service or replace. What are you going to do, shut down every road, dig up every single lead pipe, replace them all with more modern lead free ones and then restore everything months later?

        As a related aside, one could put together an entire book on the intricacies (and pros and cons) of listing services, or for profit businesses who profit from performing and mandating legally required testing, which never seems to decrease in scale or scope. In the United States, one of the common ones that sometimes people confuse for a non profit or governmental agency is the for profit company Underwriters Laboratories. There is value that these organizations provide but it can be a rather fine line between what is fair and reasonable and what is absurd and unnecessary or over reaching.

        1. Lead in pipes is either safe or dangerous depending on the water chemistry, so there may not be any logical reason to rip out old pipes in some cases, and very good reasons to do so in places like Flint. Maybe a good standard would be that the pipes have to be able to survive local water sources, not just the intended water source, because who knows when in the future people will decide to pump water in from the river or from wells.

          In the case of lead in electronics the problem is that for recycling you eventually have to expose it to exactly the sorts of chemistry that will separate the parts, and that creates an avoidable recycling or disposal hazard.

          It is well established in modern times, for example, that the Romans did not generally have lead poisoning because the chemistry of their water was safe for use with lead.

          1. I don’t think the Flint lead problem comes from household piping but pollution dumping. What about the lead foil wrapped around the mouths of wine bottles? Is that still a thing?

          2. GlueWrangler the Flint lead problem is from a combination of household and city pipework. I lived in one of the affected areas and it’s a really well known problem. The analysis was pretty conclusive that a great many pipes throughout the city were lead based alloys. Households and schools were plumbed with the appropriate pipe but soldered with lead based solder for a long time. I have replaced such pipework personally in many houses with PVC or PEX depending on what the client wanted. The worst part is that we began to use PVC in the area pretty early compared to the rest of the country but the lead was still being carried into the household either by sediment in the hot water heaters or from the city pipework. It’s very common to see sections of road dug up from pipework in the city where lead based pipe was replaced with slightly more modern pipework that doesn’t contain any harmful alloys.

      2. Define “increase”. EMC, environmental, and safety standards constantly change to reflect changes in technology and the way a product is used. The only major increase seen for last 20 years has been environmental regulations, where most (if not all) changes have been from elected officials. Whereas EMC and safety standards are only driven indirectly by governments, and are are largely the work of NGOs.

        For example, look at IEC62368-1. This standard will replace at least two other safety standards and is much less prescriptive and offers the manufacturer an approval route via engineering rationale and other mitigation.

        But please do not allow me to confuse you with the facts, which are no matter because most of my posts are deleted.

      3. There are these product certification standards, and then there are the codes that are used to create buildings, homes.

        I would propose the the issue of increasing requirements is with CODES like NFPA or NEC and can get too onerous. One bad thing happens to someone somewhere, usually due to their own ignorance or even blatant abuse, and then we all pay. Call it an un-lottery. The odds are 1 in a million that a particular bad thing will happen to you, as demonstrated by some Darwin award winner. But then the other 999,999 have to pay more per unit so the bad thing can’t happen to them… or the situation might not even apply. Unfortunately the extra safety comes with new nuisance issues, or higher cost per unit.

        The old concept of statistical improbability (collateral damage or acceptable losses) evolved to a probabilistic approach… if a bad thing can happen, however rare, it will happen to someone… what can we do to prevent it?

        Here is one example… Arc-Fault Circuit Breaker…. it was originally intended to protect bedroom circuits to afford more time to escape a home fire. The manufacturers saw this as good cause these AFCI cost 3x to 5x more than a regular circuit breaker. Since the manufacturer sits on the code committee, now ALL the home load panel breakers must be AFCI. Cost of a new home electrical panel can be thousands of dollars for the CB alone!

        There are many such examples. We would have to start a new forum discussion of these liability based unlottery items.

        1. Well the fun thing about statistics is no one wants to be THAT ONE “acceptable loss”, or “collateral damage”. Fine for the OTHER person. Kind of like “death panels” writ large, or “virgin sacrifice” to volcano god. Sucks to be you.

        2. Sorry… incorrectly or not it’s your example of Arc Fault Circuit Breakers have me suspect you would have issue with any if not all fact based code recommendations. Even as I’m not a fan as how the insurance sector in general, and especially when they manipulated the data to justify raising what they charge us for coverage, when the data is merely coincidental and doesn’t reveal a cause. Counter intuitive for the financial, Insurance(NAPA\NEC), manufacturing, and trade sectors to support onerous codes that makes it too expensive for the consumer to purchase what they are selling. The NEC are recommendations that municipalities and other insurance sectors can adopt as is, or eliminate some standards and add more onerous code if they choose. Yes ignorant people doing ignorant things cost the rest of us, so what? Until people begin being born knowing everything, their is no know about everything, every is ignorant to some degree. A forum on the topic would be inserting and even beneficial if posts where kept factual; http://forums.hackaday.com/ is still a thing it appears, inform the editors at hackaday know when yo get round to setting one up.

    3. Oh you want to use a barcode? You have to register it first and we are the only company who registers barcodes. Oh you only want one? That costs even more. Economy of scale and all, right?

    4. Such black and white thinking…. it barely qualifies as thinking at all.

      If there was no certification process then we would all be a lot worse off. The only people to benefit from that would be the ones selling fire fighting equipment! But… if you really think that what we have is the best system.. or even a very good one.. and that making money isn’t a major part of the motivation for it’s creation… You are naive!

      Think about it. What is safe is safe. What is not safe is not safe. We have formal treaties between nations regarding all sorts of things. Why does every nation have to have it’s own completely separate certification? Why can’t the nations of the developed world give us one certification that will allow us to sell our wares in each? And how much should that certification process cost? Certainly there are wages to be paid, buildings to maintain, test equipment to purchase. It shouldn’t be free. But can’t it be affordable?

      Given one well-written and openly published set of standards I bet a large portion of the readers here would be capable of developing safe widgets that meet the standard. Under the current system how many of us given an idea for a great new product could even afford to get that product certified?

      Beurocracy IS holding the progress of human technology back and this is just one example of how.

  2. I had a pretty well faked Toshiba laptop PSU that failed withing 2 weeks of purchase. Almost all safety marks were faked perfectly except for that argentinian one. It said “RAPUBUCA ARGENTINA” instead of “REPUBLICA ARGENTINA”.

      1. Ah, there’s me expecting “dA” which is perfectly valid but not a generally used SI unit.

        I( have power supplies here rated (labelled) at 750 ma and 350 ma and various totally absurd values in between.

    1. Except it actually is 240 and 220V. The UK standard of 240V was harmonized with the EU standard of 220 V by defining the standard as 230V +10%, -6%, allowing the UK to stay at 240V and the EU to stay at the 220V standard.

      1. Can you post a credible source/reference link please?
        The last time I tried to figure out how exactly the 220/230/240 Voltages in the EU where and are defined I found conflicting information.
        Schneider-Electric for example agrees with your statement but that’s not official enough for me.

        Unfortunately I’m unable to find sources conflicting with your statement right now…

      2. Oft repeated bollocks, I myself measured it and the voltage changed in 220v area from spot-on 220v to 230v. They even said that it would reduce the lifetime of various appliances by a percentage at one point.
        Now for completeness could someone in Britain please put a damn multimeter on their mains and tells us what they get? TIA

    2. It is highly unlikely you’ll receive 230V in Europe, but you will find a bunch of people using various other voltages who agree to call them 230V.

      Just like in the US we agree not to split hairs between the terms “110V” and “120V” because anything in the range 100-120V~ 50-60hz can all be called “110V” or “120V” and it darn better work for both, and it darn better work at 100V even if nobody asked for it to be rated as such.

      230V is Europe’s attempt to create the same blanket term, but there is still confusion over the purpose of the numbers; some pedants still think they are mathematical numbers rather than category labels! LOL

  3. “In general, the more certificates you see on a product, the more widely distributed their fake is and the more effort they’re wiling to invest in printing them on the housing to be sure it sells.”

    Fixed that for you.

  4. I think it is worth pointing out here, that CE mark, and maybe CCC and some others too, are just declarations of conformity. This means that by printing the mark, the manufacturer declares that the product fulfils all mandatory requirements. For some product categories (typically e.g. household electronics) no one else than the manufacturer needs to test the equipment or even look at it. It still may or may not conform to all directives and requirements and be safe to use.

    Then e.g. for medical devices a notified body must inspect the equipment, but how do you as a user know if they have done that? Or if all the markings are fake?

    At least for UL you should have the listing number and it is possible to check online if the marking is valid (or the product is good enough fake).

  5. cUL is good for Canada, similar to CSA and applies to the entire product. But the RU mark is for a *recognized component* only. That means the relay, or transformer inside the product will have an RU label. Or an OEM power supply that is mounted inside product. The RU (or cRU) will not certify the entire product, only components that are sold within it.

    What escapes a lot of manufacturers or importers is that when applying for a UL certification for USA, they can get Canada too with cUL for a small fraction of the total certification cost.

  6. i see those on non charger power supplies like the power bricks for hard drives

    i always thought the ce was the fcc, consumer safety and ul in one.

    here in the united states most government regulators are separate except for the atfe where they handle guns, liquor cigarettes and the bomb squad

  7. I bought a 12V DC 1Amp output 100-240 VAC 50-60 HZ input power supply here in the US to charge some ham radio equipment while on a trip to the UK. Upon plugging it into the outlet in a nice Airbnb in Edinburg, sparks flew out. It had worked in the US just fine, but apparently the UK voltage was too much. It was a Chinese product with all the apparently appropriate certifications. I bought it at Skycrafters Surplus, so who really knows the origin.

  8. BTW the CE european sign doesn’t mean the product is tested by any authority but rather the manufacturer “guarantees” the product conforms “declaration of conformity” with the standards applicable.
    Theoretically it means nothing, especially if you can’t track down the source.

  9. I would have thought benchoffstan would be a net exporter of thingamajigs
    It should be a real place with cryptocurrency as standard currency (or if you dont like that trade in 10k 0603 resistors)
    couple of hundred square miles of central US would do the job
    And no laws to destroy our fun with electricity and cars

  10. HEY! ” and the output amperage must be at least as big as the previous supply and it can be bigger. ”

    Beware! If it’s an unregulated power supply, if you’re not consuming the rated current, then the voltage might be higher than stated! A “9V 300mA” plugpack can be 15V open-circuit. This is mostly older power supplies which are just a transformer, rectifier (usually bridge), and capacitor. They would have a single, specific input voltage rather than a range from 110-240V.

  11. “You won’t see the manufacturer removing critical components to shave costs at the expense of safety.”

    What does the last sentence mean? Especially in respect to the whole paragraph.

    Wouldn’t cheap companies remove parts, without regard to safety?

    Also, what is mean by factory line lockdown?

    Great article, by the way. Thanks!

  12. What about the lines — indicating polarity? Solid, with dashed line under:
    – – –

    Do my power supply specs differ due to USB-C out on one, and 7.4 mm barrel on the other?

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