Mini power supply - legit or death trap? - Page 1
Forum section: electronics / beginners

author: Lucky-Luka
author_rank: Unknown
timestamp: May 07, 2022, 08:09:51 am
content: Hi allI was looking for a power supply for my Arduino based PCB.I have found this item:https://www.az-delivery.de/it/products/copy-of-220v-zu-5v-mini-netzteilThere is its datasheet in that page and its marked as CE...Any thoughts?

author: bd139
author_rank: Super Contributor
timestamp: May 07, 2022, 10:12:26 am
content: Probably fine.The PCB design you use for it, if certain standards are not met such as creepage, termination etc, is likely to be more dangerous than the power supply module.

author: kripton2035
author_rank: Super Contributor
timestamp: May 07, 2022, 10:23:26 am
content: same modules herehttps://www.aliexpress.com/store/group/Module-d-alimentation-ca-cc/4296027_513414642.htmlhalf the price. you only have to wait 15-30 days for delivery.I already bought some from this seller. they works fine.

author: elekorsi
author_rank: Regular Contributor
timestamp: May 07, 2022, 10:53:06 am
content: You have them also from Meanwell, it is the IRM seriesHere you have one that has the same power as the one on your link.https://www.tme.eu/si/en/details/irm-03-5/built-in-power-supplies/mean-well/IRM-03-05 means 3W, 5VYou can choose between different power ratings, check their website...

author: kripton2035
author_rank: Super Contributor
timestamp: May 07, 2022, 01:45:09 pm
content: Quote from: Mechatrommer on May 07, 2022, 11:27:26 amno it's really not this inside. it's a different kind of supply.

author: Lucky-Luka
author_rank: Unknown
timestamp: May 07, 2022, 03:40:21 pm
content: What is TME? Is is legit?

author: elekorsi
author_rank: Regular Contributor
timestamp: May 08, 2022, 06:24:23 am
content: One of the main suppliers in europe... i order from them 1-2 times per week. If i order before 13.00, it is delivered next day

author: Ice-Tea
author_rank: Super Contributor
timestamp: May 08, 2022, 07:06:11 am
content: A brick like this just about burned down a mates house. I have been warning him about Alibaba special orders and he's always shrugged it off.It was part of a fan controller he used for his server cabinet. A spike on the grid took out the module and burned the controller to a crisp. For good measure, it destroyed his UPS (which should not have been possible, but hey...).The Alibaba special did not have any overvoltage protection on the PCB even though the datasheet for the module clearly listed it as a requirement.Bottom line:- get a reputable brand (such as the mentioned Meanwell)- get one with a datasheet clearly indicating which external components are required (and follow the instructions rigorously)

author: janoc
author_rank: Super Contributor
timestamp: May 08, 2022, 08:04:57 am
content: Quote from: Lucky-Luka on May 07, 2022, 03:40:21 pmhttps://www.tme.eu/Originally Polish company but they have offices all over Europe now. Completely legit.

author: Ian.M
author_rank: Super Contributor
timestamp: May 08, 2022, 10:30:39 am
content: AZ-Delivery are a German company that seem to have at least *some* idea what they are doing with respect to safety. e.g. their relay modules are only rated for max. 50V AC, not the 220V-250V that is claimed by most cheap Chinese relay modules, and they are unlikely to want to risk selling CE marked stuff under their own brand name that they don't have the compliance paperwork for.However I'm not sure whether I would trust their PSU modules if the output cant be grounded in your application, as even if the design is sound, there are so many ways for a Chinese contract assembler to screw you over and its very hard to inspect a potted module after assembly. If it passes a HIPOT test and the output can be and *is* grounded to mains PE, I personally would be reasonably happy with it.

author: wizard69
author_rank: Super Contributor
timestamp: May 09, 2022, 11:15:13 am
content: Well first it depends upon your board and how you implement it. Once you have line voltage on an Arduino you need to have the proper safety implementation. That includes properly isolated line voltages and a cabinet or chassis that keeps you out of contact.As for the power supply itself, I have no idea with respect to that brand. Board mounted bricks like this are pretty common these days but you need to source from a reliable manufacture. Cheaping out on a power supply is generally a bad idea with a microcontroller or something larger like a PC.Another point; I generally prefer that a power supply be off board. Power supplies are often the failure point and if you are left with replacing and entire PCB due to a power supply failure you will end up with a frustrated customer. This especially in the embedded world where a board might run 20 years. Obviously there are different requirements but if you put a power supply on board it ought to be a reliable one.Quote from: Lucky-Luka on May 07, 2022, 08:09:51 am

author: TimNJ
author_rank: Super Contributor
timestamp: May 09, 2022, 01:27:28 pm
content: For any AC-DC power supply, intended for connection to mains, I’d like to see a UL or ETL mark printed on the housing or label. This indicates at least one 3rd party safety approval on the unit. It’s not an absolute guarantee of good quality, but it is a start. CE and double insulated mark mean pretty much amount to nothing.

author: mikerj
author_rank: Super Contributor
timestamp: May 09, 2022, 06:17:12 pm
content: Never mind the quality of the PSU module, I'm more concerned that they advertise it as "breadboard compatible". Encouraging some noob to hook up 240v to their breadboard seems less than ideal.

author: metrologist
author_rank: Super Contributor
timestamp: May 09, 2022, 07:59:40 pm
content: like a dream come true

author: Ian.M
author_rank: Super Contributor
timestamp: May 09, 2022, 08:48:02 pm
content: AARGH! ZZZZZZAAAAAAPPPP!!!Right, that "breadboard compatible" drops my confidence in AZDelivery PSU modules to a pretty low level, though still slightly above the Chinese resellers cr@p.I should however confess to having built mains powered circuits with similar PSU modules on stripboard, though I did strip tracks with the aid of an Xacto knife and a soldering gun to achieve more than adequate creepage and clearance distances.

author: bd139
author_rank: Super Contributor
timestamp: May 09, 2022, 09:34:51 pm
content: Quote from: metrologist on May 09, 2022, 07:59:40 pmThat's hilarious. Nearly spat my hot chocolate all over my laptop

author: tepalia02
author_rank: Regular Contributor
timestamp: May 14, 2022, 10:59:05 am
content: I do not think there will be any problem if you do not touch the component with a bare hand. To be in the safe side, I prefer using some kind of enclosure.

author: AndyBeez
author_rank: Frequent Contributor
timestamp: May 16, 2022, 02:44:06 pm
content: Seriously?This looks like the kind of AliExpress module that YouTube's Big Clive does a video on: "Seriously lethal micro power supply module thing... with schematic"I would feel safer reusing theun-switched modepower supply from a dead 240V LED light bulb and sticking the PCB inside a plastic TicTac box. After writing 'CE' on the outside, plus 'TUV' and 'UKCA' for good measure, I will fill the box with sand to absorb the arc/magic smoke for when theprotection diodedies.Let's keep power bricks off Arduinos! And Raspberry Pi's.

author: ebastler
author_rank: Super Contributor
timestamp: May 17, 2022, 06:50:43 pm
content: bd139 said it in the very first reply, but I'll word it differently:It does not really matter whether the power supply module is well-designed inside. For a rank amateur (like the OP, based on this and other questions he asked), there are just too many things one can get wrong when designing the PCB and enclosure around this module.@lucky-luca --pleaseuse a wall wart or other well-designed, fully encapsulated supply which only outputs extra-low voltage.

author: ConKbot
author_rank: Super Contributor
timestamp: May 18, 2022, 04:13:06 pm
content: +1, a module like that, regardless of supplier isn't a finished product. The rest of a power supply needs to go with it. Fusing, surge protection ,(see post above by Ice Tea), probably some EMI filtering, and an enclosure to keep people's grubby mitts away from mains.

author: Infraviolet
author_rank: Super Contributor
timestamp: May 20, 2022, 09:42:16 am
content: For a quick 5V supply I'd tend to suggest getting a good quality mini/micro/C USB phone "charger" and buying an adapter board which breaks out USB to 2.54mm pins. Raspberry Pi branded power supplies are a good option, if a bit pricier, up to 2A and a fairly stable regulated 5V voltage, and no "smart" stuff which tries to cut off power if you draw too small a current and ignore the data lines entirely (some other USB chargers may need those pulled high or low to supply power).

author: langwadt
author_rank: Super Contributor
timestamp: May 20, 2022, 10:27:19 am
content: Quote from: Infraviolet on May 20, 2022, 09:42:16 amUSB standard "dedicated charger" identifies itself by having the datalines shorted together