EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: Kamkut17 on June 27, 2016, 01:04:30 pm
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A while back (like, 2 months or so) I asked about programming an LCD screen into being a voltmeter/ammeter, Some people said I should get one of those digital ones they sell on ebay from china. Decided to buy this:
http://www.ebay.ie/itm/262455986278?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT (http://www.ebay.ie/itm/262455986278?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT)
Thought it would come with some kind of wiring guide (dont know WHY I thought these chinese products would come with anything)
but it didnt, so I did a bit of scavenging on the web to find a design, found this
(http://consoletronix.com/image/cache/data/Voltmeters/voltmeter-ammeter%20ckt1-500x500.JPG)
The problems I ran in with this one, was that there was 3 thick wires and 2 thin ones, while my one was opposite (colours were the same though). Well, no problem, just swap them around. Right? Wrong.
I wired it to a regular lm317 voltage regulator circuit, and my lm317 went really hot, like, as if I shorted it out hot (hint).
Decided to probe around with my continuity tester, and I found that the 2 thick red and black pins were shorted out. (Not only that, but the middle of the 3 pin connector was shorted right along with them).
(http://i.imgur.com/yazciIO.jpg)
I didnt consult back to the seller, because quite frankly, I dont care about the 3 euro I spent on this thing, also, if you also bought this product (or a product quite like it) I would appreciate if you showed me how you wired it, as right now I have absolutely no clue as to how to go about this. Thanks for reading.
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Hello.
Don´t trust everything from the Net...
Hope, this helps:
(https://www.eevblog.com/forum/projects/a-really-really-dodgy-digital-voltmeter-ammeter-from-singapore/?action=dlattach;attach=236320;image)
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All done and working, thank you!