HiLetgo 2pcs 0.28" Digital Voltmeter Ammeter DC 100V 10A Amp Voltage Current Meter Tester 0.28 Inch 3 Bits Blue + Red Dual LED Display Panel with Connect Wires

These are great little meters. I have 4 of them that I used to moniter power supply outputs and they work great,

I am an electrical engineer with extensive experience in digital electronics. I used two of these meters to replace defective analog meters in a power supply. I found the connection diagram easy to use but both meters in the 2-pack are showing incorrect voltage and current readings. After much searching for documentation I discovered that when connected to a power supply using that power supply to power the display that the thin black wire must be left unconnected. With that fix the two calibration adjustments worked.

I have used these on various projects and they work very well. A very good value.

I've been in electronics 50 years, and I had good, calibrated equipment to evaluate these. They are completely unusable for amperage. They read about 75% higher than they should, which was way out of the range of the adjustment pot. But even after I reduced the value of the internal shunt and attempted to calibrate, the meters were extremely erratic. After cycled the power,, for example, the amperage reading would change by 30 or 40%; sometimes he would go back to the original value and sometimes not. The voltmeter calibration was way off also, outside of the range of the adjustment pot. But at least it seemed to be stable and consistent. I tried two units in a both behaved about the same. There was no hookup diagram, and people complained about that. Actually, I found the hookup to be obvious as long as you realize that the ammeter shunt is in the return (negative) line. Anyway, that will be the least of your worries in trying to use these.

Seems to be what I wanted BUT came with absolutely NO instructions, so until I install then I will not know.

I used these to incorporate voltage/current readouts into my DIY power supplies that power my vintage Commodore 64 computers. With these I can rest assured of what they are putting out. They seem to be fairly accurate & the displays can be fine-tuned I think for accuracy. The current measuring wiring can be a bit tricky but if you look at other reviews of these(and similar offerings on Amazon), you can find out how exactly to wire them successfully.

LIKE: Simple to use. Bold V and A display. Very good value for money. DISLIKE: Need to assemble in another breadboard for easy IN/OUT connections. Doesn't say how much power the unit itself consumes. The spec < 20 mA is way incomplete.

Received both of them. They arrived in static safe packaging however I'm somewhat disappointed there weren't hook up instructions, because they have more wife's than the volt meter display Im replacing. My previous only had 2 wires to hook it up, these have 2 sets of wires, 1 set of 3 (red, Black and yellow) and 2nd set of what I was expecting (usual red and black). Hooking up the way you'd thing using red and black lights up your finger real good. Went back to prod info wife's I bought it and finally found hookup diagram and can't even use it. There's nothing on there that tells Me the product has to be under a load all the time (that's how was explained to me by the person who tested one out for me so I wouldn't get fired again by it) Im sure some more experienced people would know where all the wires go automatically, but, Im not that and was wanting to swap out the current "plain" digital voltmeter display with "this" upgraded volt and amp meter display in my solar setup. For me, its a waste of my money and I'm back to looking for something that doesn't have hinky wiring or to be under a load just to get reading and most importantly, Has to be wired normal (black/Neg- & red/Pos+)

回路図も説明書も無いうえに私の知性の弱さから苦労しましたが 色々と他商品のヒントを参考に研究し理解することが出来ました 精度はあまり期待しないほうが良いかと思って 他の商品も購入することとしました。 小さな紙切れで良いので回路図くらいほしいですね

Set it up to use on a 3.3v, 5v and 12v supply but the Ammeter only works with 12v. Voltmeter works fine on all 3. All are linked through the same connections to the ammeter.

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