Difference between revisions of "Common symbols around you"

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File:PSE.png|[https://en.wikipedia.org/wiki/Act_on_Product_Safety_of_Electrical_Appliances_and_Materials PSE] (Japan)  
File:PSE.png|[https://en.wikipedia.org/wiki/Act_on_Product_Safety_of_Electrical_Appliances_and_Materials PSE] (Japan)  
File:CCC.png|[https://en.wikipedia.org/wiki/China_Compulsory_Certificate CCC] (China)  
File:CCC.png|[https://en.wikipedia.org/wiki/China_Compulsory_Certificate CCC] (China)  
File:BSMI.png|BSMI (Taiwan)  
File:BSMI.png|[https://en.wikipedia.org/wiki/Bureau_of_Standards,_Metrology_and_Inspection BSMI] (Taiwan)  

Revision as of 12:20, 26 June 2020

Uses, safety

Some mark mentioning RoHS means it's compliant to RoHS

Power supply

basic AC-to-DC adapter specs

The top symbol is for DC barrel plugs, specifying whether the inside or outside is positive.

The middle line is input, where the squiggly tilde ~ indicates AC, here mentioning an input voltage range and frequency it's okay with (these specs amount to worldwide use).

The third line (output)'s solid and dotted line indicates DC.

LPS (Limited Power Source) have relatively low maximum voltage, current, and power. [3]

SELV (Safety Extra Low Voltage), where the power supply output stays safe under single fault conditions. [4]

Transformer (general)

isolating, safety isolating;    non-short-circuit proof, short-circuit proof

separating transformer, output >1kV, variable, constant voltage, perturbation attenuating

Double circle, like a vertical venn diagram, are transformers, with a handful of properties marked. There are more combinations of all the parts this image shows, and further ones (e.g. construction site).



Some of the more commonly seen logos / certification bodies include:

Bunch on European certifications

There are actually many more testing centers, that may deal with additional health and/or safety and/or environmental concerns, and in many cases it's largerly just country-specific.

You're probably used to the logos for your part of the world.

Certification marks, in the end, represent agreements between manufacturers and (ideally well known) testing centers. (and note there are logos that do not mean that at all)

In most places these are not strictly required for sale(verify), yet certification is quite common for a collection of reasons, like you caring about your safety, for company insurance (liabilitywise), varied indirect regulation (e.g. electrical code, fire regulation, medical safety) effectively only buying certified devices, or self-imposed regulation like caring that your house doesn't burn down and for related insurance.

For some devices (e.g. separate power supplies) you can see more-than-usual certification marks, for practical reasons: e.g. when a large company that has locked down the design so that they can mass produce it, for worldwide sale, without a lot of new certification (certifcation is slow, sort of expensive, and may need periodic recertification).

CE Mark and Chinese Export
There are also a bunch of fake symbols.

Best known among them is chinese producers just stamping on the european CE mark.

Often with different, tighter spacing, presumably to to have an argument it's not the same (but this tighter spacing is also used in some CE products for spacing reasons).

This has been nicknamed "chinese export".


A bunch of markings used around mechanisms, indicators, and buttons, around cars, audio, production lines are settled in ISO 7000 / IEC 60417, see e.g. See https://www.iso.org/obp/ui#iso:pub:PUB400008:en

IP ratings for water and object safety

clothing / washing labels

Packaging symbols




Single use, keep dry, don't use if package damaged