How the? - Page 1
Forum section: electronics / general

author: tom66
author_rank: Super Contributor
timestamp: May 28, 2012, 03:11:28 pm
content: £1.98 for a 12V/24V to 240V inverterhttp://www.ebay.co.uk/itm/Car-12V-24V-AC-240V-Power-Inverter-Converter-Adapter-/300715919821?pt=LH_DefaultDomain_3&hash=item460410c9cd#ht_3539wt_1189Yeah it only delivers 5W but how an earth do they make that for £1.98 including delivery, and a profit margin...Hmm I suspect it probably outputs DC, due to the claim "Note: Please rotate your power supply plug 180 degrees to try it again if this item does not offer power." I.e. for half-wave rectified devices. Still kinda impressive.You cannot compete with China for cheap dangerous goods!

author: sonicj
author_rank: Frequent Contributor
timestamp: May 28, 2012, 06:50:31 pm
content: "Output: AC 100V- 240V "-sj

author: SeanB
author_rank: Super Contributor
timestamp: May 28, 2012, 07:24:21 pm
content: Depends on the load and the supply voltage. 110v with 12V input, 200v with 24V input100V at 1W load, 200V at no load.0V after 2 minutes as the magic smoke wafts out.........

author: DavidDLC
author_rank: Frequent Contributor
timestamp: May 28, 2012, 07:31:55 pm
content: Well, it can be stolen items from the factory, from a store or from a truck, and therefore the low price, the thief has nothing to loose.

author: SeanB
author_rank: Super Contributor
timestamp: May 28, 2012, 07:45:36 pm
content: Just how many would they have to have stolen to make a profit at that price. I would say made down to cost, and qc was a sub 5 second test to see no smoke and a neon on output lit. possibly made on ghost shift.

author: ejeffrey
author_rank: Super Contributor
timestamp: May 28, 2012, 08:00:16 pm
content: There are plenty of cheap step down 90-260 V -> 5 V / 5 watt supplies that only cost a couple of bucks. A crappy "modified sine wave" inverter with non existent safety ratings doesn't actually have to be much more expensive. If it only produces DC as indicated by the suggestion to rotate the plug there is no reason it couldn't be even cheaper. A non-isolated, unregulated or poorly regulated boost converter could be made for next to nothing.Also, this is ebay. There is no reason to think it is manufactured with the intent to sell it for GBP 1. It could be overproduction of a custom part that someone decided to dump on ebay. If it really produces unregulated DC I have a hard time imagining it being produced as a stand alone product in the first place. This has all the signs of a last minute bodge by someone who needed 12 volt compatibility for a specific product on the cheap. I could be wrong and this was produced for direct sale to consumers but never sold because it turns out there are things so crappy nobody will buy them (except of course on ebay). Or it could be stolen. There are plenty of products on ebay that are being sold for less than the cost to produce them, and often even less than the scrap value.

author: NiHaoMike
author_rank: Super Contributor
timestamp: May 28, 2012, 09:04:57 pm
content: I think it's just a cheap 60Hz transformer with a transistor or two and a few passives to make it operate as a self oscillating converter. Similar devices are used in cheap fluorescent inverters.

author: G7PSK
author_rank: Super Contributor
timestamp: May 28, 2012, 09:05:53 pm
content: I bought a cheap inverter from Maplins some years ago when I checked the output voltage it was over 700 volts RMS at half load which explained why it was blowing every thing plugged into it up the wave form looked like back to back and inverted j or hockey sticks.