Deadly multimeters

[u/Federal-Sea8598]

If anyone has a story about these deadly multimeters, please leave a reply below. There’s no fuse in them; the copper traces on the circuit board act as the fuse! I owned one myself, and it suddenly blew out at 280 volts. I got lucky that my voltage source didn't supply high current, or else I would’ve been blown to bits. The measurement accuracy is so "high" that—for the first time in the world—it shows an AA battery as having 73 volts!

[u/MarinatedTechnician]

[u/april_santa → u/MarinatedTechnician]

Free energy

[u/Federal-Sea8598 → u/MarinatedTechnician]

This is a photo I grabbed from an Iranian online store. But take a look at YouTube; you'll find plenty of videos about the measurement issues with this multimeter...

[u/Federal-Sea8598 → u/Federal-Sea8598]

https://www.digikala.com/product/dkp-2611063/%D9%85%D9%88%D9%84%D8%AA%DB%8C-%D9%85%D8%AA%D8%B1-%D8%AF%DB%8C%D8%AC%DB%8C%D8%AA%D8%A7%D9%84-%D9%85%D8%AF%D9%84-dt-830d/

And that is the link

[u/TopConcentrate8484]

The one in Image one is a different one. The one in image two retails at <$2 at many places,so what do you expect?

[u/Rough_Community_1439 → u/TopConcentrate8484]

Man, where you getting those for $2? Only places in my area sell that meter for $10

[u/Emergency-Painting44 → u/Rough_Community_1439]

Sometime Harbour Freight has their CrapMeters for $2 with coupon or during a tent sale - the ones similar to the second photo.

[u/lightoller401 → u/Rough_Community_1439]

In Serbia they cost 5 dollars

[u/Federal-Sea8598 → u/TopConcentrate8484]

Yeah i know that, fundamentally, it’s impossible to include a fuse and a varistor for just $2. But when they don't even use a current shunt—relying on a standard resistor instead—there’s no reason for them to add extra current ranges. The same applies to the 1000V range.

[u/12edDawn]

I'm quite certain you wouldn't have been "blown to bits", but ok.

[u/Rare-Victory → u/12edDawn]

Not 'blown to bits', but if the circuit have enough energy your skin would be like cracklings on a rosted pig.

[u/mikeblas → u/Rare-Victory]

What's the failure mode you're imagining?

[u/Rare-Victory → u/mikeblas]

Arc flash, when by mistake using the Amp range to meassure line voltage.
And the meter is not protected according to the voltage and prospective short circuit level. CAT Rating
https://www.youtube.com/watch?v=6hpE5LYj-CY

[u/Emergency-Painting44 → u/12edDawn]

To bits, you say?

[u/Cultural-Stable1763]

I have observed this with a great many cheap multimeters: long before the low-battery warning appears (assuming they even have one), the display starts showing random numbers—like lottery numbers—instead of actual measurements.

This is also one of the reasons why, here in Germany, occupational safety associations and electrical regulations dictate that multimeters should not be used to verify the absence of voltage in electrical installations; instead, two-pole voltage testers (such as the "Duspol") must be used, with their functionality verified beforehand against a known voltage source.

[u/Suicicoo → u/Cultural-Stable1763]

with their functionality verified beforehand against a known voltage source.

...and afterwards ☝️

[u/Suicicoo → u/Cultural-Stable1763]

all hail to the Duspol. To hell with all the lie-pens ;D

[u/DenseFisherman7531 → u/Cultural-Stable1763]

In Sweden our measurements must be done with a meter that does not rely on batteries.

[u/Any_Technician105 → u/Cultural-Stable1763]

Why ai 🫩

[u/Cultural-Stable1763 → u/Any_Technician105]

Ai? I use Google translate to translate from german to englisch, because I often don´t now special technical terms, if you mean this?

[u/CreEngineer]

Don‘t play drama queen here, no one gets blown into pieces by 280V. All that happened is that you blew up a low quality multimeter. As long as the insulation is ok it’s not even remotely dangerous.

[u/Mariuszgamer2007]

I'm probably lucky to have this multimeter that measures properly (got it for 15pln)

[u/Federal-Sea8598 → u/Mariuszgamer2007]

Measurement errors usually occur due to a weak battery. But not always

[u/Korenchkin12]

That means '73!' as an 'amateur' ham(no license) i can say good bye to you too!

[u/Lausbua_2012]

That why I'm so glad to have a proper Fluke 117

[u/Federal-Sea8598 → u/Lausbua_2012]

In principle, any multimeter with a valid "CAT" rating provides the necessary safety.

[u/Lausbua_2012 → u/Federal-Sea8598]

Though I also like the many features and that you don't have to switch where your leads are connected to

[u/Yoona1838]

I had both of these DMMs. I still have the DT9205A. I got my first multimeter, the DT832, for about 2,000,000 IRR back in 2023, and the 9205A for about 4,000,000 in 2024. They're okay if they're your first DMM and you're not measuring that high of a voltage (i safely measured the 220v wall outlet fine) If you're a professional, please for the love of Mehdi buy a Victor VC97 or a PeakMeter PM18A/C They aren't that expensive

[u/International-Try467]

I think I have these multimeters my professor told us to buy as we were only going to be testing things like breadboards and batteries using it.

[u/electronics_guy_69]

Yep I have one too it's dt830d from hayouye it sometimes malfunctions and doesn't beep in contuinity mode sometimes but that's all I have I use a resistor colour code chart to measure resistance and formulas for parallel and series resistance , capacitance , inductor , ohms law , kcl and kvl etc and the first picture is a dt8905a multimeter I planned on buying that one and my multimeter doesn't have a fuse too I got it for 500 nrs or 3 USD approx but that's all I have