Why sizes are different between 5V DC charger and power supply - Page 1
Forum section: electronics / beginners

author: teedee
author_rank: Newbie
timestamp: July 19, 2016, 05:18:49 pm
content: I'm looking for a small 10W 5V DC power supply module for my Arduino controller but when I search online, I notice that the 5V chargers are usually much smaller than those 5V power supply modules with similar power ratings. For example, thischargeris much smaller than thispower supply. Why are they so much different in size and are there any 5V DC power supply module that is as compact as a typical 5V charger?

author: Signal32
author_rank: Frequent Contributor
timestamp: July 19, 2016, 05:29:47 pm
content: The specific charger that you linked has it's current rating Photoshop'ed out. It's unlikely to actually deliver 2A. Most "2A" chargers that you will find are likely to only be 1A.The SMPS that you linked is likely to actually be able to deliver 2A. And it's not that much bigger than a power adapter(Size (L x W x H): Approx. 2.8 x 1.5 x 1.2 inch).Plus the power supply has to accommodate space for the headers and has to have some clearance from the outer metal shell (not that important with plastic shell ).The SMPS appears large in the pictures, yes, but it's not. Measure one of your 5v power adapters and see the dimensions aren't that much different.Perhaps this will give you a better perspective:

author: janoc
author_rank: Super Contributor
timestamp: July 19, 2016, 09:07:41 pm
content: Well, I probably wouldn't recommend using that type of power supply unless you are planning to actually install it in an enclosure.That isnota lab supply and is not designed to be used as-is on the bench - exposed mains terminals, only minimal case, so if you drop a piece of wire or solder it can cause a short inside (with potentially catastrophic effects), etc. That doesn't mean it is a bad supply, just make sure you use it for what it was designed for - to be embedded into an enclosed project, with proper wiring and grounding.BTW, buying power supplies on eBay from a random seller in China is a really really bad idea. For a $2 supply, what do you think will be the quality of the mains transformer, overload protection and insulation? I am pretty sure that it will be the cheapest piece of dangerous crap you could get.Don't be cheap and buy a proper supply from e.g. Digikey or another major vendor in your area. They are not much more expensive and you have at least some minimum assurance (such as UL listing) that the thing will not burn down your house or kill you. It is literally the only thing between your Arduino and the mains outlet. Or do you value your health and home so little?

author: Kilrah
author_rank: Unknown
timestamp: July 19, 2016, 09:27:46 pm
content: Just get a decent, quality USB charger that's really capable of supplying 2A. If you don't already have one laying around from another device that is.

author: Nexo
author_rank: Regular Contributor
timestamp: July 20, 2016, 12:11:37 am
content: Most USB chargers are 5V and 1A top. Is it possible to create a circuit in order to raise that 1A until 2A?

author: Dave
author_rank: Super Contributor
timestamp: July 20, 2016, 12:31:02 am
content: Quote from: Nexo on July 20, 2016, 12:11:37 amYes, it's called a cosmic ray harvester and it increases your efficiency to 200%. You have to wear a protective tinfoil hat while you are using it, though. Safety first!

author: tooki
author_rank: Super Contributor
timestamp: July 20, 2016, 01:01:27 am
content: I should test this (and can tomorrow if you like), but I'd probably just buy an Apple 12W USB power supply for $20 and call it a day. I can't think of any reason it wouldn't work admirably for an arduino.

author: Audioguru
author_rank: Super Contributor
timestamp: July 20, 2016, 02:14:34 am
content: I think there should be some organization to stop ebay from selling extremely cheap and extremely dangerous junk like those power supplies that will probably burn down your home.

author: SeanB
author_rank: Super Contributor
timestamp: July 20, 2016, 07:58:25 am
content: Quote from: Audioguru on July 20, 2016, 02:14:34 amThen eBay, Aliexpress and pretty much every strip mall would have to close.

author: Kilrah
author_rank: Unknown
timestamp: July 20, 2016, 08:49:06 am
content: Quote from: Nexo on July 20, 2016, 12:11:37 amNearly everything sold in the past 3-4 years has 2A chargers.

author: jakeisprobably
author_rank: Regular Contributor
timestamp: July 21, 2016, 04:38:12 pm
content: I like to figure out what thrift stores are in my area and move a lot of electronic stuff. They throw out an enormous number of chargers, usually because the cords get so tangled no one is willing to sort them out. I give whomever is in charge a few bucks to text me when they are going to throw them out. Bring a set of wire cutters and you'll walk away with every DC power supply you'll ever need in every spec imaginable. I especially look for car phone and laptop charger adopters (DC-DC buck/boost converters).As a side benefit, these are generally tested and proven devices that don't burn your house down.

author: Galenbo
author_rank: Super Contributor
timestamp: July 22, 2016, 02:15:15 pm
content: Quote from: teedee on July 19, 2016, 05:18:49 pmThey are designed for different environments.The steal maze typehast to be put in another enclosure, because it is not water/kids safe.The plastic typecannot be put into another encosure, it needs much air circulation or it will melt away.The only situation I know youcouldchoose both is a furniture-size ELDON/Rittal cabinet. The plastic type has the disadvantage here that you will need/occupy a 10$ DIN Socket, so place and money are away.

author: Galenbo
author_rank: Super Contributor
timestamp: July 22, 2016, 02:32:36 pm
content: Quote from: Audioguru on July 20, 2016, 02:14:34 amI think the expensive existing subsidized organisations swarm around DIN, EU, CE, TUV, VDE, EN, AREI,.. (insert +100 others here) should return to their core business, and for 1 time do what is in theirtask listinstead of only thinking about their own infinitely bureaucracy expansion.1)look if the imported device has a CE mark.-When not, no problem. User's responsability to burn their baby. Reading "CE" is possible for every adult.2)When it has a CE mark, see if it is legal (legal test reports, certified bodies etc)-When it has a "legal" CE mark, good. The EXISTING regulation is fine. (but applied poorly)3)When it has an fraudulent illegal CE mark, ban the company+owners+ceo+distributor+... personally from theinternational market. Burn/recycle all their products.4)When there is procedural doubt without de-facto real-life danger, provide fast 2-way feedback.5)Periodically test random devices, and make +Y2K style youtube reports about this.