Thanks for the heads up, Dwayne. I had an interesting but somewhat opposite experience a few years ago. I bought a really cheap car cell phone charger (one of those which claims to be able to charge all brands of cell phone and comes with lots of little adaptors). It also came with an adaptor which was simply a two-prong AC plug and a car cigarette lighter receptacle in a plastic body.. None of the items had any approval or regulatory marks on them (UL, CE, etc.) and they didn't even have ratings or a brand name marked on them - that info was only on the package that it came in. I highly suspected that they were not actually designed to meet the regulations and were never evaluated at all. However, both the car charger and the AC adaptor for it worked. Eventually, I took apart the AC adaptor expecting to find a silly capacitor voltage divider with no isolation but I was pleasantly surprised that it contained an actual proper isolated switching power supply. So, I think the moral of the story is that these kinds of items are hit or miss and need to be evaluated on an individual basis. Sean On Sat, Jan 7, 2012 at 5:33 PM, Dwayne Reid wrote: > Good day to all. > > I was looking for some cheap mains-powered mini-USB and micro-USB > (5V) power supplies a few months back and purchased some from > eBay. =A0They've been sitting on the shelf until a few weeks ago. > > Upon going to use one of these units for the first time, something > odd caught my eye. =A0Although the input voltage rating is 100V - 240 > Vac, the output voltage was shown as 4.5-9.5 Vdc @ 800mA. =A0This > seemed odd but I didn't really pay much attention to it. > > I ran one of the micro-USB supplies on the cute little Gabotronics > micro-sized DSO / MSO units that I purchased a while back. =A0Seemed to > work OK for that purpose. > > When I went to go play with the Gabotronics unit again, the power > supply was dead. =A0I didn't have another unit with a micro-USB plug on > it, so I opened the unit up with an eye towards fixing it. > > But - I'm not going to bother. > > This thing is total piece of excrement. > > One each power and small-signal transistors in the front end - and NO > feedback voltage regulation (!!). =A0It really looks as if this thing > was designed to supply about 4.5V with 100Vac at the input, rising to > about 5V with 120Vac input and getting all the way to about 9.5V with > 240Vac input. > > In other words, its a fixed ratio power supply with absolutely NO > regulation whatsoever. > > Failure was input fusible resistor open and power transistor > shorted. =A0Didn't even bother to see if the small-signal transistor is O= K. > > I'll use these things as a source of micro and mini USB power cables > but I'm not going to trust the power supplies to power anything that > I want to keep. > > Just thought that I'd put the word out to keep an eye out for these > things. =A0I can see someone who lives in a 230Vac part of the world > being bit rather badly by the 9V or so output when they were > expecting 5V. =A0Talk about "Ouch!" !! > > dwayne > > -- > Dwayne Reid =A0 > Trinity Electronics Systems Ltd =A0 =A0Edmonton, AB, CANADA > (780) 489-3199=A0voice =A0 =A0 =A0 =A0 =A0(780) 487-6397 fax > www.trinity-electronics.com > Custom Electronics Design and Manufacturing > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .