Hobbie multimeter - Page 1
Forum section: electronics / testgear

author: htrv
author_rank: Newbie
timestamp: October 26, 2024, 06:30:07 pm
content: Hey guys,I'm sorry if I'm repeating a question that was asked before, but the multimeter thread doesn’t seem to update, and I hope that maybe newer multimeters have come out.I'm looking for a cheap multimeter (up to $50 USD) for home and hobby use (electrical work, fixing home appliances and computers, and microcontroller projects).Basically, I’m looking for a good backlit screen, ergonomic controls, reliable continuity function with a beeping sound, and reasonably accurate measurements. Any extra features would be welcome (like capacitance measurement, temperature, BT, etc.).The UNI-T UT61E is out of my budget, so I was looking at the ANENG AN870 (which has better specs) and the UNI-T UT60BT (which looks better built).Hope you could share some experiences with them... Or maybe suggest other models?

author: Aldo22
author_rank: Super Contributor
timestamp: October 26, 2024, 06:42:42 pm
content: ZT-225 is imo the best really cheap DMM.https://zotektools.com/products/zoyi-zt-225/https://www.aliexpress.com/item/1005007244323221.htmlBut it's not a pocket meter!

author: iet
author_rank: Frequent Contributor
timestamp: October 26, 2024, 07:36:42 pm
content: I use the PCW02A multimeter. The multimeter has a good set of functions. The continuity tester is loud, supplemented with a light indicator. Measurements of frequency, temperature. Measurement of capacitance up to 100 mF. Voltage detector.The price is within the range that you indicated.https://pcworktools.com/wp-content/uploads/2020/11/pcw02a-user-manual-digital-multimeter-pcwork.pdf

author: GigaJoe
author_rank: Frequent Contributor
timestamp: October 26, 2024, 09:14:53 pm
content: have a drawer full of dif. kind. AN870 are OK .. most annoying measure resistance.. as the logic of measure are simple- from very top to bottom , take a long time ... very annoying to measure bunch of unknown resistors ...have that 25000 count as well - really nothing special , and no precision ; for cheap extended range would be interesting HP-770D 40000, also in my drawer; it very useful to measure lithium cells due to 42000 counts limit .... not expecting much precision ... but its OK ....my favorite OWON B41T+ ; I don't know why for some reason more preference even over UNI-t ( had overclocked it - doubled quartz value - double speed, 10 measure\sec now, any resistance -0.4 sec, Bluetooth gone of course , but with that speed never go back)vey like AN8008 for $20bottom line --- get AN8008 or 8009 or something even more cheaper like dt9205a or something to fix the fridge ... and if it blow up don't cry too much..and something expensive like with scope combined ; as it seems trend ; i have owon scope\multimeter unit and it really useful to see and evaluate signals , without heavy duty gears involved ...something like thishttps://vi.aliexpress.com/item/1005007761538584.html; but of course ... more money wide bandwidth ... but still better then nothing

author: coromonadalix
author_rank: Super Contributor
timestamp: October 27, 2024, 08:41:01 am
content: an UNI-T UT61E out of your budgetall under 50$ meters are mostly good or gimmicks ohms diodes etc .. but not high voltagesif you play in voltages say 120 vac 220,230, 240 vac, save money and buy reputable brands, don't cut corners in security .... it's your lifeyou can find good used meters like Brymen, Fluke, Wavetek, Beckman .... many Uni-t meters are toys tooi understand price can be very difficult .... BUT ...

author: Aldo22
author_rank: Super Contributor
timestamp: October 27, 2024, 09:09:10 am
content: Quote from: coromonadalix on October 27, 2024, 08:41:01 amFUD again!You're not going to die any sooner because you're repairing household appliances with an AN870 or ZT-225 instead of a Fluke.That's nonsense.

author: DavidAlfa
author_rank: Super Contributor
timestamp: October 27, 2024, 09:13:18 am
content: How are you going to die? Fully isolated plastic case. Even if something shorts internally, the DMM will die and that's it.Don't come with that video exploding DMMs with giant HV capacitors, "See how it's unsafe?".UNI-T gives decent quality por the price, has safety gaps in the PCB...The 890C/D is really cheap and works fine.

author: iet
author_rank: Frequent Contributor
timestamp: October 27, 2024, 09:34:40 am
content: Safety is a serious matter and should be the first priority. I compared my PCW02A and FLUKE117. Everything is fine with safety.PCW02ASafety InstructionsThe instrument is designed according to the requirements of the international electricalsafety standard IEC61010-1, which defines the safety requirements for electronictesting instruments. The design and manufacturing of this instrument strictly complywith the requirements of the IEC61010-1 CAT.III 1000V, CAT. IV 600V over voltagesafety standards and pollution level 2.FLUKE117Safety IEC 61010-1: Pollution Degree 2IEC 61010-2-033: CAT III 600V

author: Fungus
author_rank: Super Contributor
timestamp: October 27, 2024, 09:41:12 am
content: UNI-T UT61E is a waste of money unless you NEED the serial data connection. It's not particularly good or safe or anything else compared to ANENG/Zoyi.(Most ANENG meters are rebrands of Zoyi models)You ALWAYS need more than one meter, so for $50 I'd get:A ZTS1 for poking at mains:https://www.aliexpress.com/item/1005004478400063.htmlA fast/fun meter to use and quite idiot-proof for mains (even if it's not CAT rated, it's automatic and beeps at you if you have the lead in the wrong hole). Decent continuity test. The big downside to them is they don't measure voltages below 0.8V.Something like a ZT302 or ZT303 for more delicate work:https://www.aliexpress.com/item/1005007797711956.html(nb. You don't need more than 10,000 counts, you just don't...)Note: Randomly chosen sellers.

author: Fungus
author_rank: Super Contributor
timestamp: October 27, 2024, 09:52:42 am
content: Quote from: iet on October 27, 2024, 09:34:40 amTrue, but safety is as much about procedures and using your brain as owning a fancy multimeter. A meter that's hard to put the dial/probes in the wrong place helps as much as anything.You're alsoveryunlikely to die or blow things up if you're working in a place with circuit breakers, RCDs, etc. You might get a scare but that's about it (unless the scare makes you fall off a ladder or something).Your wiring would have to beseriouslydefective for death to happen.Not downplaying it, but being realistic. Engaging the brain is at least as important as the meter.

author: csuhi17
author_rank: Frequent Contributor
timestamp: October 27, 2024, 10:11:13 am
content: It is not safe, poor quality, poor handling and the price does not match your needs.Owon HDS120 ~$70Owon CMS101 ~$120Maybe they will release it with better parameters, maybe not.

author: iet
author_rank: Frequent Contributor
timestamp: October 27, 2024, 05:14:28 pm
content: Good information from FLUKE.https://www.fluke-direct.com/files/fluke-multimeters-detecting-intermittents-u.pdf

author: Aldo22
author_rank: Super Contributor
timestamp: October 27, 2024, 05:45:23 pm
content: Quote from: Fungus on October 27, 2024, 09:41:12 amWell, they cost almost the same as the ZT-225.I don't recommend the ZT-225 (only) because of the 25000 counts, but because it is simply better in everything.You can't get more bang for the buck or more accuracy for the money.For example, 20A is simply safer to use with the usual Lab-PSU than just 10A. Because the 10/11A are then guaranteed without blowing the fuse or overheating.In certain respects it is also better than the AN870, e.g. it has more positions for the rotary knob. So I don't have to press any secondary buttons for the measurements (Resistance / Capacitance / Diode..)Then it has more information on the display. When measuring AC, I can see the frequency at the same time, which gives me immediate reassurance that I'm measuring the right thing.AC/DC measurement is also quite practical.In the attached photo you see 1Vdc with a 5mVrms AC “ripple” at a glance, without a scope.Etc...I like it and it costs $30.

author: Fungus
author_rank: Super Contributor
timestamp: October 27, 2024, 09:15:01 pm
content: Quote from: Aldo22 on October 27, 2024, 05:45:23 pmTrue, but until you've poked around a microcontroller circuit with one of those fully-auto meters you just don't get how fun/fast they are."That should be 5V, yep. That should be ground ('beep'), yep. This should be 3.3V...", all without touching a dial.And you often want to clip a couple of meters onto a circuit to watch values as things change.(get some crocodile clip leads, too)

author: Aldo22
author_rank: Super Contributor
timestamp: October 27, 2024, 10:21:53 pm
content: Quote from: Fungus on October 27, 2024, 09:15:01 pmMyANENG ST212clamp meter works in “Auto” mode for most types of measurement (And the SMD tweezers too).Is that what you mean?

author: BillyO
author_rank: Super Contributor
timestamp: October 27, 2024, 11:51:15 pm
content: Give some consideration to the Kaiweets HT118E.20,000 counts, auto-ranging, very solidly made, and extremely accurate. Will certainly suffice for Cat I and CAT II environments. Probes are of decent quality and the continuity is fast, loud and latched. It's right at the top of your budget but it's worth every penny. I've had one since a few weeks after their introduction and for electronics work it holds up just fine against my Brymen BM-786 and even auto-ranges faster, all for 1/3 the price.https://kaiweets.com/products/ht118e-20000-counts-digital-multimeterI'd also like to add that the HT118E also sports a dual display of voltage and frequency in ACV mode, plus frequency and duty cycle Hz mode, which a lot of the other meters mentioned here do not have.

author: BillyO
author_rank: Super Contributor
timestamp: October 28, 2024, 12:02:40 am
content: Quote from: Aldo22 on October 26, 2024, 06:42:42 pmLooks pretty good spec wise. What's it like internally?

author: Aldo22
author_rank: Super Contributor
timestamp: October 28, 2024, 09:03:57 am
content: Quote from: BillyO on October 28, 2024, 12:02:40 amAre you talking about safety?Could be better - could be worse. It has two ceramic fuses and a couple of PTCs. It's $30...I don't think it will kill you while you're fixing the toaster.Personally, I don't use it for mains power (I hardly ever deal with mains anyway). I use it for electronics.If I have to do anything with mains power, I use the handierST212. It shows me with NCV whether there is voltage on the wire and, if required, how much current is flowing.All contactless in this case, or with a single test lead “Live Wire”.ZT-225 has NCV too, but it's actually too clunky for that imo. ZT-225 is more like a portable benchtop meter that runs on batteries.Quote from: BillyO on October 27, 2024, 11:51:15 pmZT-225 also has that.In the attachment 10kHz with 25% duty.

author: EEVblog
author_rank: Unknown
timestamp: October 28, 2024, 09:26:10 am
content: Quote from: Fungus on October 27, 2024, 09:41:12 amWhy?The UT-61E has been one of the go-to cheap meters for like a decade now. Most people don't use it for serial.It's still excellent value for money.Are there better bang-per-buck meters now? Almost certainly, but it's still a fine option.

author: Aldo22
author_rank: Super Contributor
timestamp: October 28, 2024, 09:30:52 am
content: Quote from: EEVblog on October 28, 2024, 09:26:10 amIt is no longer available anyway.https://www.batronix.com/versand/multimeter/multimeter-ut61e.html

author: Fungus
author_rank: Super Contributor
timestamp: October 28, 2024, 09:51:24 am
content: Quote from: EEVblog on October 28, 2024, 09:26:10 ama) We new have meters like the Aneng 870.b) Can you still get new ones? It was replaced with this:c) The thing I really hated was that there were many variants of it and you never knew what as going to be inside any particular one.

author: Aldo22
author_rank: Super Contributor
timestamp: October 28, 2024, 10:10:33 am
content: Quote from: Fungus on October 28, 2024, 09:51:24 amUT161E is well over €100.The topic starter wanted something for a maximum of $50.

author: Solder_Junkie
author_rank: Frequent Contributor
timestamp: October 28, 2024, 11:19:06 am
content: At the cheap end of the meter market, you might struggle to find a meter that is independently certified for safety. The problem that can arise is when you accidentally use the meter on Ohms or current across the mains.Other posters were criticised for mentioning safety, it is a serious matter. Meters can and do explode, or burst into flames. See this YouTube video shot in a Fluke factory if you don’t believe me:https://youtu.be/OEoazQ1zuUM?feature=sharedSJ

author: Aldo22
author_rank: Super Contributor
timestamp: October 28, 2024, 11:26:19 am
content: Quote from: Solder_Junkie on October 28, 2024, 11:19:06 amZT-225 has no problems with that:https://youtu.be/UIml3TYDomE?t=316

author: coromonadalix
author_rank: Super Contributor
timestamp: October 28, 2024, 11:44:14 am
content: Quote from: Solder_Junkie on October 28, 2024, 11:19:06 amthey will learn the hard way .... happened to see one bust, and it was not "in the so cheap price" ...if the ZT-225 survives that its another plusthe common mistake is : meter set in the current / probes in the current when probing the voltage (s) i know i did this mistake too loll, 11$ a fuse

author: Fungus
author_rank: Super Contributor
timestamp: October 28, 2024, 11:57:15 am
content: Quote from: coromonadalix on October 28, 2024, 11:44:14 am...which is why you choose a meter with no "wrong" dial position and beep alerts when the probes are in the wrong sockets.Even ifit's a cheap meter, like the Zoyi I mentioned.

author: Fungus
author_rank: Super Contributor
timestamp: October 28, 2024, 12:03:05 pm
content: Quote from: Solder_Junkie on October 28, 2024, 11:19:06 amTrue, but Harbor Freight has given awaymillionsof DT130s with remarkably few deaths.I couldn't even find one on google.

author: Aldo22
author_rank: Super Contributor
timestamp: October 28, 2024, 12:42:33 pm
content: Quote from: coromonadalix on October 28, 2024, 11:44:14 amI'll never "learn" that, because I don't have a 750V like these guys and I don't see this DMM being used in that range anyway.Quote from: coromonadalix on October 28, 2024, 11:44:14 amWell, if the price of the replacement fuse is your biggest problem...

author: EEVblog
author_rank: Unknown
timestamp: October 29, 2024, 04:14:20 am
content: Quote from: Fungus on October 28, 2024, 12:03:05 pmMultimeter safety is a tad overrated, and has been pushed toward the extreme end of the OH&S spectrum.That's not a bad thing of course, in fact it's great, but people do get a tad carried away.Sure the general recommendation of "CAT III for anything mains related and above" is good general advice, but it's not needed.Most people do not work on such high energy systems to warrant being that worried about it.And basically it's limited to only one fault scenario, probes in the A jack by mistake when measuring mains or another high energy system.The whole peak overload thing (e.g lighting strike on the mains) is so remote an issue that it's almost not a thing.For example, my latest pocket meter (the 1980s) coming out soon was going to be CAT II, whcih would be fine for a pocket meter, but the new standard says you are no longer able to brand CAT I or CAT II on the front of a meter any more, you can only brand CAT III and above. So they did a few design tweaks to get it to CAT III standard so it could be printed on the front, lest anything think it has "no CAT rating".So all new meters should (if they follow the standards for third party approval) either have CAT III/IV printed on them, or nothing at all.

author: BillyO
author_rank: Super Contributor
timestamp: October 29, 2024, 04:37:30 am
content: Quote from: EEVblog on October 29, 2024, 04:14:20 amYeah, there maybe other issues in play for folk that take out their DMM and start probing their breaker panel at the height of an electrical storm. Perhaps they are striving for a Darwin award.I have noticed that a lot of the newer meters on the market have either dropped any CAT rating at all or just say Cat III.Feck, about 50 years ago I worked in what would be described as CAT IV environments today with a Simpson 260 meter. We didn't have anything much better at the time. I'm still here today.I'd love to see a comparison between the number of fatal injuries suffered by people using budget meters to measure their mains versus the number of fatal injuries suffered from driving the family sedan to the local grocery store.

author: floobydust
author_rank: Super Contributor
timestamp: October 29, 2024, 05:02:09 am
content: I wonder if it didn't start as a marketing angle. Fluke touted multimeter safety in the 80's and patented the common (MOV) protection circuit. It locked out any other manufacturers (which was a disservice) from using a similar scheme and then they were pushing safety standards 1010 etc. and had pretty much exclusive approval.I think what matters is a multimeter was actually tested at high voltage. Creepage/clearance is a common place for design error, as well as the safety parts like the fuses, PTC, test leads etc.For OP and $50 I think a multimeter that does not die easily is also important. It's on Ohms and you connect to a voltage whether 12V or mains OOPS. I think DT-830's bite the dust there yet many different designs/builds of them.I would avoid UNI-T as they are intentionally stupid cheap inside and as a brand they are proven to have problems being honest.Many DMM reviews here:https://lygte-info.dk/info/DMMReviews.html

author: wasedadoc
author_rank: Super Contributor
timestamp: October 29, 2024, 12:56:06 pm
content: You can get a low cost TUV certified CAT III 300V meter such ashttps://www.ebay.co.uk/p/21045215038. Basic volts, amps, ohms, diode, continuity. No capacitance, temperature etc. (Manual athttps://customer-service.lidl.co.uk/SelfServiceUK/s/product2?productId=01t6N000000X2r1QAC&q=pdm%20300) Lidl stores have that Parkside one in the special buys every so often but also some sellers on ebay, typically 15 to 20 Euros. Use that for household mains etc. (Review)For electronics also get the likes of an Aneng 8008 or any of the similar makes/models.Under 40 Euros total for the two.

author: Aldo22
author_rank: Super Contributor
timestamp: October 29, 2024, 07:59:59 pm
content: Quote from: wasedadoc on October 29, 2024, 12:56:06 pmWhich DMM would you trust more?A TÜV certified CAT III 300V meter, which only shows garbage above 300V, or an uncertified CAT III 1000V meter, with a 1000VDC / 750VAC measuring range?

author: tooki
author_rank: Super Contributor
timestamp: December 26, 2024, 12:46:44 pm
content: Quote from: Aldo22 on October 29, 2024, 07:59:59 pmWhat makes you think it would show garbage above 300V? It will either do what many, many meters do and show “OL”, or do what many, many meters do and actually measure accurately voltages above the rating.Remember, CAT ratings are about safety, not measurement accuracy.

author: Aldo22
author_rank: Super Contributor
timestamp: December 26, 2024, 01:09:18 pm
content: Quote from: tooki on December 26, 2024, 12:46:44 pmBecause it is shown in the video above (from about 12:30), if I understand correctly.

author: BillyO
author_rank: Super Contributor
timestamp: December 26, 2024, 03:20:35 pm
content: It's only rated to 300V maximum. Why would expect it to measure properly over 300V?Do you make measurements over 300V often?To answer your question though I'd trust a $15 meter certified to 300V more than a $15 meter uncertified claiming 1000V any day.

author: Aldo22
author_rank: Super Contributor
timestamp: December 26, 2024, 03:37:35 pm
content: Quote from: BillyO on December 26, 2024, 03:20:35 pmI would expect it to show “OL” or something like that and not some BS value.Quote from: BillyO on December 26, 2024, 03:20:35 pmNo, not even 230V, which is why I'm not interested in all these death fantasies.Quote from: BillyO on December 26, 2024, 03:20:35 pmIwouldprefer a meter that can measure 1000V instead of displaying some crap.But as I said, that's pure theory for me.

author: BillyO
author_rank: Super Contributor
timestamp: December 26, 2024, 03:47:35 pm
content: Quote from: Aldo22 on December 26, 2024, 03:37:35 pmIt clearly did at 500V. It only misbehaved at 1000V which is considerably more than 3 times it's rated voltage. My guess is that the people that made this expect the people that buy it to ream the manual and not abuse it to the point of having a death wish. You will note though that even at 1000V it survived.QuoteWell, if it's all just theory why stop at 1000V? What do you think your $15 1000V meter would display if you put 1200V on it?? Or how about 3300V? Would you even try those voltages to find out?

author: EEVblog
author_rank: Unknown
timestamp: December 26, 2024, 09:55:05 pm
content: Quote from: Aldo22 on December 26, 2024, 03:37:35 pmProper high voltage meters are available, like the Uni-T UT892 or UT196

author: mwb1100
author_rank: Frequent Contributor
timestamp: December 27, 2024, 06:12:10 pm
content: The Fluke 101 doesn’t have a backlight, but other than that I think all the requirements are met. It doesn’t have whiz bang features, but does the basics well. And no one will be able to claim it’s poorly designed or built.Amazon has it for just above $50 (in the US anyway)Edit: I forgot it doesn’t measure current, so that might be a deal killer if no backlight isn’t already

author: Aldo22
author_rank: Super Contributor
timestamp: December 27, 2024, 06:36:11 pm
content: This thread is 2 months old.The topic starter has never given any feedback.I think further answers to the initial question and more Fluke advertising are not useful.

author: tooki
author_rank: Super Contributor
timestamp: December 27, 2024, 08:07:41 pm
content: Quote from: Aldo22 on December 26, 2024, 03:37:35 pmThey aren’t fantasies. They’re just not common, and are a risk in certain situations. The fact thatyouare never in those situations doesn’t mean they’re fantasies.The hazard isn’t from voltage, by the way, but from current. 230V/400V mains at the outlets is protected by circuit breakers in your panel (consumer unit) to limit current to a small amount, which is why measurements downstream of the panel are only CAT I. The dangers come when measuring e.g. where the power enters the building, coming from a substation. The short-circuit current is thousands and thousands of amps, and that won’t blow their upstream fuse. Industrial mains power can be similarly powerful.If a meter manages to cause a short on that, the short instantly vaporizes the thinnest part of copper, creating a cloud of plasma — and plasma is highly conductive, so current keeps flowing. The vaporized copper needs a much larger volume than the solid copper, so it creates an explosion. And it’s hot. Really hot. That fireball is what is dangerous.Of course, no hobbyist should ever be doing anything on that side of the mains supply. But they might by accident/stupidity.

author: wasedadoc
author_rank: Super Contributor
timestamp: December 27, 2024, 11:45:37 pm
content: Quote from: tooki on December 27, 2024, 08:07:41 pmIn the UK only an authorised engineer working for or on behalf of the supply company should be able to probe the supply side of the main fuse. In my case that is a 63 Amp one. Both sides of that fuse and the subsequent live and neutral connections to the consumption meter are totally enclosed requiring the breaking of seals to gain access. No right-minded hobbyist would be trying to measure before the supply company's fuse when there are easily available places after the fuse.

author: BillyO
author_rank: Super Contributor
timestamp: December 28, 2024, 12:14:56 am
content: Quote from: wasedadoc on December 27, 2024, 11:45:37 pmIn Canada (Ontario), you have access to the line coming in directly from the meter. In fact, I wired it up myself (the whole house, actually). The only requirement is that you take out a permit and have it inspected by the electrical safety authority. There is an additional cover over that end of the panel, but there are not any seals or restricted access. Just 4 screws away.I especially like to get in there a start probing around with a cheap meter when there are lighting storms.

author: Aldo22
author_rank: Super Contributor
timestamp: December 28, 2024, 08:22:26 am
content: Quote from: tooki on December 27, 2024, 08:07:41 pmFor me, these are fantasies. You're describing a danger that I won't or can't possibly put myself in.I'm not an electrician and I'm not interested in that.I live in a modern apartment building (5 years old) and have no access to dangerous areas at all.If I had access, I wouldn't touch these areas, not even with a fluke and not even out of stupidity.What would be the point?The biggest danger I run into is perhaps measuring a PSU plugged into the socket.I don't know why you keep warning people about dangers that don't even apply to them.And why should inexpensive DMMs be the biggest danger? That's a distortion of reality imo.You might as well warn me about the dangers of a hypersonic flight.I'm not interested becauseI don't do that.

author: tooki
author_rank: Super Contributor
timestamp: December 28, 2024, 09:05:12 am
content: Quote from: Aldo22 on December 28, 2024, 08:22:26 amQuote from: tooki on December 27, 2024, 08:07:41 pmJust because something isn’t applicable to you doesn’t make it “fantasy”.Dragons are fantasy. They are nonexistent.Alligators are not fantasy, even though our chances of randomly encountering one in Switzerland are zero.

author: Aldo22
author_rank: Super Contributor
timestamp: December 28, 2024, 09:25:27 am
content: Quote from: tooki on December 28, 2024, 09:05:12 amThat's a quibble (“Wortklauberei, Spítzfindigkeit”).Of course alligators exist, but if I'm plagued by the fantasy that an alligator is eating me in bed in Switzerland, then I should see a doctor.

author: RAPo
author_rank: Super Contributor
timestamp: December 28, 2024, 09:37:44 am
content: Well eating is a bit much, but alligators have been seen inSwitzerland in 2019.

author: Aldo22
author_rank: Super Contributor
timestamp: December 28, 2024, 10:11:08 am
content: Quote from: RAPo on December 28, 2024, 09:37:44 amRight, I had forgotten about that one...

author: tooki
author_rank: Super Contributor
timestamp: December 28, 2024, 10:25:55 am
content: Quote from: Aldo22 on December 28, 2024, 09:25:27 amNo, it isn't. Words matter in discussions, especially in arguments, and even more so in a forum full of engineering pedants!

author: Fungus
author_rank: Super Contributor
timestamp: December 28, 2024, 10:27:34 am
content: I'm sure there's thousands of American probing their mains feed with free Harbor Freight meters as we speak.

author: tooki
author_rank: Super Contributor
timestamp: December 28, 2024, 10:36:06 am
content: Quote from: RAPo on December 28, 2024, 09:37:44 amActually, no.1. It was initially suspected of being a caiman, which is related to an alligator, but is not an alligator.2. It was later determined to not be a reptile at all, but awels catfish:https://www.tagesanzeiger.ch/raetsel-geloest-das-ist-der-kaiman-vom-hallwilersee-662416332905

author: Aldo22
author_rank: Super Contributor
timestamp: December 28, 2024, 10:55:16 am
content: Quote from: tooki on December 28, 2024, 10:25:55 am"Fantasy" is not a technical word and your concept of it is too narrow.Perhaps something is lost in translation, but there is, for example, the term “suicide fantasy”. Based on this, I used the term “death fantasy” - half-jokingly.“Suicide fantasy” doesn't mean that suicide doesn't exist, but that the thought of it haunts me.Just as certain people are apparently haunted by the idea that the DMM wants to kill them.But we'll leave it at that. It's more psychology than electronics.

author: Fungus
author_rank: Super Contributor
timestamp: December 28, 2024, 11:46:55 am
content: Quote from: Aldo22 on December 28, 2024, 10:55:16 amThere's a lot of those here.It's nice to know that a meter isrobustbecause inductive spikes are real and we don't want to kill our meters just by connecting them to a few turns of wire at 5V but there aremanypeople here who think buying less than an industrial-plant rated meter is a death wish.

author: wasedadoc
author_rank: Super Contributor
timestamp: December 28, 2024, 01:05:50 pm
content: Quote from: BillyO on December 28, 2024, 12:14:56 amYes, basically the same in the UK and I expect most countries. No access at any point before the customer side of the usage meter. (Otherwise bypassing the meter and stealing electricity would be too easy and tempting.) The main fuse is on the supplier side of the meter. So no way a hobbyist at home should be exposed to the full unfused capability of the supply network.

author: BillyO
author_rank: Super Contributor
timestamp: December 28, 2024, 02:56:44 pm
content: Quote from: wasedadoc on December 28, 2024, 01:05:50 pmHere the main breaker is on the customer side of the meter. Since circa 1980 I think, all new detached homes were fitted with 200A service. I built my house in 1990 and was required to put in a 200A service @220V CT. It comes in through a 200KVA pole mounted transformer which feeds 3 other properties.

author: Fungus
author_rank: Super Contributor
timestamp: December 28, 2024, 03:08:51 pm
content: Quote from: wasedadoc on December 27, 2024, 11:45:37 pmIt's the same here in Spain.Anecdote: A while back my neighbor called me because the lights didn't work. Turns out a circuit breaker had tripped so it was an easy fix but while I was inside the breaker box I noticed the twisted-wire seal was missing from the cover of the "big breaker". Go figure.

author: Aldo22
author_rank: Super Contributor
timestamp: December 28, 2024, 03:42:30 pm
content: Instead of scaremongering, how about we define in which situations this whole “safety” story is relevant at all?In other words, for whom is it worth buying an expensive fluke or similar and for whom is it a waste of money?Let me start (RFC)- For those who only sit behind their 30V/10A power supply, all these considerations are irrelevant.- Anyone who does anything with cables coming from the socket should watch where he has his fingers. Whether Fluke or Zotek makes no difference in terms of life expectancy.- Anyone working in hazardous areas should have the training of a professional and use professional tools.Right?

author: Fungus
author_rank: Super Contributor
timestamp: December 28, 2024, 05:27:38 pm
content: Anybody who pokes around in dangerous places should wear at least one glove and eye/ear protection but I bet very few people here do.(look at the photos on the Fluke web site - theyallwear PPE)Yes, my big complaint is that the people here telling others not to buy "unsafe" metersalwaysfail to mention safety procedure. It's as if the meter itself will save you.It's almost safer to buy a cheap meter and be afraid of the wires than use an expensive meter with overconfidence.

author: HKJ
author_rank: Super Contributor
timestamp: December 28, 2024, 05:59:07 pm
content: Cheap meters are safe when working with low voltage (i.e. 12-30V).Cheap meters are mostly safe at mains voltage (120-230V) at domestic current levels.Cheap meters are unsafe at industrial settings, i.e. lots of amperes (50+) with voltage at 230 and above.A industrial installation with 100's of amps and 600V will easily kill you if yo make a mistake (that is also true for a safe meter, but a smaller mistake are not as serious as with a cheap meter).

author: joeqsmith
author_rank: Super Contributor
timestamp: December 29, 2024, 01:53:12 am
content: Quote from: Aldo22 on December 28, 2024, 03:42:30 pmI don't want them for their safety. I want them because they are electrically and mechanically more robust.Sitting behind a 30V @ 10A power supply, then to my DC-DC at 4000V @ 50mA. Safe to touch? Its behind the power supply so I guess it is safe. I then use that to charge my 100uF capacitor bank. 1/2CV^2... 800Joules. Safe to touch? Sounds like it should be. After all it is behind that safe power supply. Personally, I am not going near it no matter what you claim.In other words, I want a meter that may actually survive if I do something stupid.***Stupid, like using it to discharge my microwave oven's capacitor.

author: bdunham7
author_rank: Super Contributor
timestamp: December 29, 2024, 03:36:35 am
content: Quote from: Aldo22 on December 28, 2024, 03:42:30 pmStart by not presuming that Fluke customers are primarily concerned with being incinerated by arc-flash. We, or at least I, are not contesting that your ZT-225 is reasonably safe for use on low-voltage up to and including single-phase household mains that don't exceed the 250VAC rating of the fuse. The CAT rating would imply it is suitable for much more but I don't think I'd like to rely on that. I would especially recommend that you avoid using it on any HVDC solar systems and maybe think carefully before probing any mains-powered SMPS units. And, of course, microwave ovens are to be avoided unless you have the proper tools (I do) and some idea of what you are doing. Beyond that it is more a case of what is going to kill your meter rather than what might kill you.

author: Zoli
author_rank: Frequent Contributor
timestamp: December 29, 2024, 06:56:33 am
content: Quote from: joeqsmith on December 29, 2024, 01:53:12 amOver 1kV you should use a HV probe; so if you do something like described above, you can only blame yourself.

author: EEVblog
author_rank: Unknown
timestamp: December 29, 2024, 07:36:12 am
content: Quote from: Aldo22 on December 28, 2024, 03:42:30 pmI see the whole CAT rating thing as serving two purposes:1) as a nice rule of thumb.If you do anything mains rated regularly, or would like your meter to stand a better chance of surviving some random incident either dumb or unknown, then it's best to get at least a (genuine) CAT III rated meter. Not essential, but nice.2) For companies that need a known minimum standard so their arse is covered. For most people this doesn't apply, even the likes of professional electricians. It's not like an electrican can't get insurance if they aren't using a CAT IV rated Fluke meter for example.This is why the new 61010 standard has removed the CAT I and CAT II ratings frm the front panel of meters, so you aren't potentially confused when you glance at that CAT rating on the front of the meter.Only CAT III/IV meters are now allowed to have CAT printed on the front of them.If you really really really care about robustness and high voltage then you'll get one of the newer high voltage rated meters that are now being made for the solar industry. And even then you are likely using special probes for stuff.

author: Aldo22
author_rank: Super Contributor
timestamp: December 29, 2024, 09:18:14 am
content: Quote from: joeqsmith on December 29, 2024, 01:53:12 amQuote from: bdunham7 on December 29, 2024, 03:36:35 amI understand, but these are considerations that primarily concern professionals or "hardcore hobbyists" who use the devices in hard, daily use.I have about seven inexpensive meters, some of which have been around for decades and all of them still work. At most, a mA fuse blows once in a while.For example, if you buy a ZT-225 or an AN870 for $27, the DMM probably costs less than the fuse on a “decent” meter.Why should I care as a hobbyist who doesn't venture into dangerous areas?It makes no sense to me economically or in terms of event probability.

author: EEVblog
author_rank: Unknown
timestamp: December 29, 2024, 10:08:46 am
content: Quote from: Aldo22 on December 29, 2024, 09:18:14 amI'm a multimeter dealer, I've sold 10's of thousands of them.The number that have been returned due to external electrical overload damage is zero.

author: Muttley Snickers
author_rank: Unknown
timestamp: December 29, 2024, 10:24:02 am
content: I blew up a meter recently just checking the point contact on my old Scott Bonnar lawn mower.It happened in an instant when I put the meter in low ohms range and without thinking slowly rotated the flywheel which induced a voltage from the ignition coil and destroyed the meter. This was the first multimeter I ever bought so I've had it since 1990, and one of the very few meters I own which had no input protection whatsoever. RIP Dick Smith Q1425

author: Traceless
author_rank: Frequent Contributor
timestamp: December 29, 2024, 10:30:23 am
content: Quote from: Fungus on December 28, 2024, 10:27:34 amWhich is not necessarily a good idea.Quote from: Fungus on December 28, 2024, 05:27:38 pmBut a good meter has its merits and absolutely can save you under certain circumstances as demonstrated in the video below.PPE/safety measures are important, however I've yet to see an electrician wearing gloves and safety glasses working on household mains. I also doubt that most people put on safety glasses or gloves when changing a light bulb. I think one of the most important safety measures in this case is to turn off the breaker *and* then double check that there is no power present which is best done with a "safe" meter. The Harbor Freight freebie style meter doesn't seem to be one of those.https://youtu.be/OEoazQ1zuUM?feature=shared&t=375The video also demonstrates joeqsmith's point - with a "proper" meter you may get away with making a stupid mistake.Also on the original topic and the Uni-T 61E which seems to be over budget - maybe a Brymen BM231 is a decent choice closer to the OPs budget.

author: Fungus
author_rank: Super Contributor
timestamp: December 29, 2024, 10:37:46 am
content: Quote from: Traceless on December 29, 2024, 10:30:23 amI like putting on the lights (and/or plug in a lamp) and make sure they go off.

author: Aldo22
author_rank: Super Contributor
timestamp: December 29, 2024, 10:41:21 am
content: Quote from: Traceless on December 29, 2024, 10:30:23 amOK, but this is clearly Fluke advertising.The fact that they apparently have to compare the absolute cheapest junk to show the superiority of their devices is not exactly praiseworthy either.There are enough videos that show that a Zotek (Zoyi, Aneng, Richmeters, Kasuntest...) can withstand quite a lot.

author: Traceless
author_rank: Frequent Contributor
timestamp: December 29, 2024, 10:43:00 am
content: Quote from: Fungus on December 29, 2024, 10:37:46 amThe bulb is off because it is broken, to do the lights test you'd need to get a new one in first - so that test only works when you're done with the potentially dangerous procedure. Testing some other outlet is not safe it might be on a different breaker. You test the socket you're working on.

author: Fungus
author_rank: Super Contributor
timestamp: December 29, 2024, 11:04:17 am
content: Quote from: Traceless on December 29, 2024, 10:43:00 amThat'll be the "plug in a lamp" part.Quote from: Traceless on December 29, 2024, 10:43:00 amYou make sure they go "on" first. You can even turn them on/off a couple of times with the breaker. There's really not much need to use a multimeter at all.How do you trust your multimeter without a proving unit?

author: Aldo22
author_rank: Super Contributor
timestamp: December 29, 2024, 11:09:42 am
content: ZT-225 and AN870 have NCV.This is good for testing if there is power on it and it is safe unless you fall off your chair...

author: Traceless
author_rank: Frequent Contributor
timestamp: December 29, 2024, 11:12:28 am
content: Quote from: Fungus on December 28, 2024, 05:27:38 pmFor someone who was so adamant about safety procedure you really try to weasel around safe procedure.Quote from: Fungus on December 29, 2024, 11:04:17 amI don't know how things are in the area you live but here ceiling lights have a socket usually E27 or E14. So you can not plug in a bulb you have to screw it in. Unlike Power outlets those sockets are big an you can get your fingers in really easy. So that is why you deactivate power before changing the bulb.Quote from: Fungus on December 29, 2024, 11:04:17 amTaking a measurement at a socket before turning off the breaker and make sure it shows 240 VAC. Then turn the breaker off and make sure there is no voltage present. If the meter breaks between those two measurements - tough luck.

author: Fungus
author_rank: Super Contributor
timestamp: December 29, 2024, 11:24:48 am
content: Quote from: Traceless on December 29, 2024, 11:12:28 amYou don't wear gloves?

author: Fungus
author_rank: Super Contributor
timestamp: December 29, 2024, 11:26:50 am
content: Quote from: Traceless on December 29, 2024, 11:12:28 amWhy would you be "working" on a socket that shows 240V AC?

author: Traceless
author_rank: Frequent Contributor
timestamp: December 29, 2024, 11:33:28 am
content: Quote from: Fungus on December 29, 2024, 11:26:50 amI wouldn't that is why I use a meter to make sure there is no voltage present?Quote from: Fungus on December 29, 2024, 11:24:48 amWhat is your point? Forget about turning of the breaker and make sure you switched off the right one, because everything will be fine if you wear gloves?

author: madires
author_rank: Super Contributor
timestamp: December 29, 2024, 01:22:04 pm
content: Quote from: Fungus on December 29, 2024, 11:26:50 amWhat Traceless has explained above is a basic safety precaution tought to sparkies and other related professions over here. The idea is to check if your T&M gear works, i.e. that it can detect/measure mains voltage and also the lack of. This is part of the "5 safety rules".BTW, for mains related work I'd recommend to use specialized T&M gear like a Duspol. Typical DMMs aren't suited well for that.

author: Aldo22
author_rank: Super Contributor
timestamp: December 29, 2024, 02:03:07 pm
content: Somehow I can't quite follow.Is it really safer to poke around in a lamp socket with the multimeter test leads than to simply hold the bulb by the glass and screw it in (perhaps with gloves, for the very careful)?I can't imagine that. Are there any statistics on this?As I said, NCV helps.

author: Xena E
author_rank: Frequent Contributor
timestamp: December 29, 2024, 02:13:04 pm
content: For proving a high energy electrical circuit a general purpose multimeter is not really the preferred equipment, and being safe doesn't need to be expensive in equipment cost, just as a basic example, A Fluke T90 can be had for as little as 50 quid new.In the industrial setting I would say that technicians not proving disconnections and not putting shorting links on remote high energy circuits are the biggest source of accidents, perhaps only behind circuit identification mistakes, and multiple source "gotchas".PV and their inverters are good traps for the unwary...As for using cheap multimeters, I'm not knocking them, they're great value things, and safe when used within their ratings and with common sense.My routine for working on any part of a fixed electrical installation is:Prove the testing device.Identify the circuit.Switch off the breaker,and lock it off, plus tag the circuit as isolated.Prove the circuit is dead.Prove the testing device.If you do not have control over the operation of the breaker then fit a suitable shorting link on the circuit.X

author: tooki
author_rank: Super Contributor
timestamp: December 29, 2024, 02:25:37 pm
content: Quote from: Aldo22 on December 29, 2024, 02:03:07 pmYeah that part of the discussion went off into the weeds… 😂In the end, everyone is agreeing that you want to first prove your mains detection test device (whether a light bulb or a meter) works by proving it on a live circuit before using it to test the circuit to be turned off for work. They just don’t realize they agree on this because they’re arguing in circles around misunderstandings.

author: bdunham7
author_rank: Super Contributor
timestamp: December 29, 2024, 03:08:50 pm
content: Quote from: Aldo22 on December 29, 2024, 02:03:07 pmThat brings up an important point--test leads, specifically the tips. Proper CAT III/IV test leads (yes, test leads and probes have CAT ratings and requirements) will have a minimal amount of exposed tip to reduce the chances of you shorting out something big. You can start an arc-flash (high energy installations) or splatter molten metal blobs into your eyes (at home) more easily with bad probing than with even the cheapest of multimeters.I'm not a fan of NCV in a multimeter, I prefer the separate tool. Single-lead voltage detection is better, but I find the most reliable NCV to be tools like Klein NCVT-1 or Fluke 1AC.

author: madires
author_rank: Super Contributor
timestamp: December 29, 2024, 03:14:24 pm
content: Quote from: Aldo22 on December 29, 2024, 02:03:07 pmIIRC, the context was about checking if a circuit is disconnected. Let's assume you're working on a lamp socket. A bulb would only indicate if (sufficient) current is flowing or not. It doesn't tell you if neutral or live is switched, if there's some coupled voltage from another wire, or if neutral and live might be swapped.Quote from: Aldo22 on December 29, 2024, 02:03:07 pmWhat will an NCV tester tell me when there's coupled voltage from another wire?

author: Aldo22
author_rank: Super Contributor
timestamp: December 29, 2024, 03:27:27 pm
content: Quote from: madires on December 29, 2024, 03:14:24 pmI have no idea what you're talking about.I thought it was about a broken light bulb, where you want to see if there is current on the socket before replacing it.Whatever the purpose....Personally, I would just screw in a new one, regardless of the switch being on or off, like probably 99.9% of people who don't get confused by electronics forums.

author: tooki
author_rank: Super Contributor
timestamp: December 29, 2024, 03:39:35 pm
content: Quote from: Aldo22 on December 29, 2024, 03:27:27 pmNnnnnno friend, it wasn’t about replacing a blown light bulb.

author: madires
author_rank: Super Contributor
timestamp: December 29, 2024, 03:49:40 pm
content: Quote from: Aldo22 on December 29, 2024, 03:27:27 pmIf you want to check that for whatever reason it would be the same procedure. Maybe I should add that what someone is doing at home at his own risk might not be what a sparky would do when following safety rules (for safety, liability, insurance and compliance reasons).Quote from: Aldo22 on December 29, 2024, 03:27:27 pmI fully agree, that's what most would do.

author: joeqsmith
author_rank: Super Contributor
timestamp: December 29, 2024, 05:52:39 pm
content: Quote from: Aldo22 on December 29, 2024, 09:18:14 amI suspect there are many more people who share your opinion. There is a reason so many low cost, unprotected meters are sold. As mentioned, just look at the free meters that harbor freight gives away.But as you suggest, we are not all the same. You feel sitting behind a 30V @ 10A power supply is safe where I consider that this 300W could easily mess you up. You haveQuoteI have my first Fluke which is also decades old which I damaged so may times because it has no input protection that I finally retired it. Cost too much to repair. Call me advanced, stupid, what ever else you like but there is a reason I want robust tools. You don't have such a need so save your cash. No big deal.

author: Fungus
author_rank: Super Contributor
timestamp: December 29, 2024, 06:01:08 pm
content: Quote from: Traceless on December 29, 2024, 11:33:28 amHow do you know if that socket is working or not?

author: Aldo22
author_rank: Super Contributor
timestamp: December 29, 2024, 07:02:03 pm
content: Quote from: joeqsmith on December 29, 2024, 05:52:39 pmSure, but there's also something between Fluke and "harbor freight".With the ZT-225, for example, you can change the ranges without any problems, even if 230V is applied to Vin (something I would never do...).https://youtu.be/UIml3TYDomE?t=314There are also tests with the AN870, which apply 4kV to Vin and nothing happens, the meter works normally afterwards.But as I said, this is not what I would use it for.

author: joeqsmith
author_rank: Super Contributor
timestamp: December 29, 2024, 07:13:07 pm
content: Quote from: Aldo22 on December 29, 2024, 07:02:03 pmSure, there is a very wide variance of products available and I've looked at a few of them, including ANENG. Suggesting a meter can handle 4kV without any proof or further details is useless, wouldn't you agree? There is a reason I will state I test a meter at 4kV peak, 100us FWHH, 2 ohm source. I may even show the waveform. I want to be very clear about what I am subjecting them to. There is a big difference between that and say 4kV AC RMS, or a 4kV HBM ESD event wouldn't you say?

author: floobydust
author_rank: Super Contributor
timestamp: December 29, 2024, 07:31:04 pm
content: Engineering is an applied science, we do TESTING. This is what safety standards are about as well.Rather than sow confidence and certainty based on emotions or a psychological "feeling".Multimeter incidents with arc flash do happen with most resolved out of court. chinese products commonly have misleading, fraudulent claims about their agency approvals.Do your own research and you will see that we (the West) allow this to continue and nothing can be done legally against them.Example is a big name chinese manufacturer multimeter with purported 61010 approvals and arc flash happened in USA. It was found to have inadequate spacings amongst other bullshit. It may have been only certified to the low voltage directive, as a 3V device not to be used over 50V input. This is another common loophole used.

author: Aldo22
author_rank: Super Contributor
timestamp: December 29, 2024, 07:47:38 pm
content: Quote from: joeqsmith on December 29, 2024, 07:13:07 pmI don't understand much about it and I'm not particularly interested in anything above 30V.You can watch the video. I don't know how much sense it makes what he does.Apparently the device survives the test though.https://youtu.be/dAN96tYoe3c?t=4251But I'll say it again, I don't do that sort of thing and I would not recommend an AN870 for high voltage.Please let's not have this pointless discussion again.

author: joeqsmith
author_rank: Super Contributor
timestamp: December 29, 2024, 07:57:35 pm
content: Quote from: Aldo22 on December 29, 2024, 07:47:38 pmLOL. Ok, I suspect even the harbor freight meter would have no problems with what he is showing.

author: Simmed
author_rank: Frequent Contributor
timestamp: December 29, 2024, 08:15:13 pm
content: hmmm in the foil wrapped video partparts of the test leads are wrapped, his leakage is over 70uA @ 4kVas comparisonlong ago i tested some PTFE twisted pair cable (about 24AWG) 1m length with 1kV and it has around 10ish uA leakfirst i would question, is his test lead rated for 4kV ? i think most are only 1kVso i dont know about what to concur from the videoQuote from: Aldo22 on December 29, 2024, 07:47:38 pm* as a curious search onlinemedical device rated power should not leak more than 1mA (iec-60601)but this is a test meter, do they have a leak limitation test criteria like medical / iec code ?

author: Aldo22
author_rank: Super Contributor
timestamp: December 29, 2024, 08:38:39 pm
content: Quote from: Simmed on December 29, 2024, 08:15:13 pmIf these are the ones supplied, then they are rated 1000V.Quote from: Simmed on December 29, 2024, 08:15:13 pmActually I don't either. I picked up the video and thought “cool 4kV”, but the more I think about it, the less I know what to conclude.The DMM is also apparently switched off during the test...Best to forget about it.

author: joeqsmith
author_rank: Super Contributor
timestamp: December 29, 2024, 09:29:44 pm
content: I think I did something similar early on to look at insulation. I don't think what he is showing is wrong, but I am more interested in conducted susceptibility. This is why I constantly state my interest in IEC 61326.

author: joeqsmith
author_rank: Super Contributor
timestamp: December 29, 2024, 09:35:54 pm
content: Dave made a video once where he was cycling some device with his power supply and damaged it. I wasn't able to find that video but maybe this would be of some interest.https://youtu.be/hReCPMIcLHg?t=843***Found it. Watch the first 2 minutes. It's good to have tools that are robust enough to survive some basic transients. But to your point, if you are just measuring your AA batteries and 1k resistors, none of this matters.

author: Aldo22
author_rank: Super Contributor
timestamp: December 30, 2024, 11:15:24 am
content: Quote from: joeqsmith on December 29, 2024, 09:35:54 pmInteresting video.What can I learn from it?"Expensive devices will also break, better buy cheap ones to be less annoyed"?Yes, expensive is relative, but you can get 10 DPS-150 for one DP832 (no, I don't really want to compare these devices).Quote from: joeqsmith on December 29, 2024, 09:35:54 pmExactly!In the attachment you can see my super cheap “Lab” with DPS-150 trying to measure a 0.1Ω resistor.19.188mV / 190.52mA = 0.1007ΩA bit awkward, but it works.This is my little world. Everything fits into a drawer.

author: Fungus
author_rank: Super Contributor
timestamp: December 30, 2024, 11:34:22 am
content: Quote from: Aldo22 on December 30, 2024, 11:15:24 amThat even the little 5V coil inside a relay can destroy things if you're not careful.

author: Aldo22
author_rank: Super Contributor
timestamp: December 30, 2024, 12:06:02 pm
content: Quote from: Fungus on December 30, 2024, 11:34:22 amSure, but if it happens to an experienced David L. Jones, it can happen to anyone.The only question then is, how expensive the damage is.

author: Fungus
author_rank: Super Contributor
timestamp: December 30, 2024, 01:19:23 pm
content: Quote from: Aldo22 on December 30, 2024, 12:06:02 pmWhen I let the kids at Arduino club play with motors I get them to put a backwards LED in parallel with the motor so they can learn.When you turn the motor off you see a flash. That's inductance...You can put a long string of LEDs and they'll still flash - the voltage goes as high as needed to find a path. Lesson: Be afraid of inductors.

author: joeqsmith
author_rank: Super Contributor
timestamp: December 30, 2024, 01:48:21 pm
content: Quote from: Aldo22 on December 30, 2024, 11:15:24 amIndeed. I dare say of the equipment I own, the higher the cost, the more specialized they are and the easier to damage.Where I live, ESD can be a problem. Recently I suspect I damaged one of those low cost VNAs with ESD while handling it. A while back I was doing a series on 3-D printed horn antennas, looking at their radiation patterns. While testing I was not wearing a strap. I rolled my chair across the plastic floor mat. Got up and touched the horn (which was grounded through some coax cable). This event damaged a small amplifier. I think the IC was under $30, so not the end of the world.Of course, something like my scopes would cost more to repair. Because of the custom parts used and their age, may not be repairable. Normally I wear a strap.

author: joeqsmith
author_rank: Super Contributor
timestamp: December 30, 2024, 03:02:00 pm
content: Quote from: Fungus on December 30, 2024, 01:19:23 pmOf course, we could create high voltage using capacitors as well.https://en.wikipedia.org/wiki/Cockcroft%E2%80%93Walton_generator

author: floobydust
author_rank: Super Contributor
timestamp: December 30, 2024, 09:25:53 pm
content: Hobby multimeters can still be dangerous - measuring low voltage on Arduino projects etc. all is well- but in the blink of an eye you need to repair an appliance, stove/dryer etc. and go taking measurements in the 240VAC world.Got a DT-830D gift from a Taiwan trade show, wondered if it's better quality than the mainland.Took it apart and looked at the clearances - could I keep it around in the toolbox as a junker? Use for mains measurements?How many mm are people thinking is adequate, or do I instead need to make an offering to some deity to keep it safe lol.So far this thread says yes "she'll be alright"

author: Fungus
author_rank: Super Contributor
timestamp: December 31, 2024, 05:52:25 am
content: Quote from: floobydust on December 30, 2024, 09:25:53 pmYMMV.Quote from: floobydust on December 30, 2024, 09:25:53 pmI don't know without seeing photos. I know Harbor Freight gives away millions of them in the US and there hasn't been a big lawsuit due to people dying.If I absolutely had to get a really cheap meter for the people who look at batteries/mains with DT830s I think I'd go with this:https://zotektools.com/products/zt-s2/(or the more advanced model:https://zotektools.com/products/zoyizt-s4/)It's the poor man's Fluke 113. There's no dial to mess up, just switch on and use. It (tastefully) beeps and flashes a red light at you when the lead is in the current jack, and it feels completely indestructible.(nb. you switch to current measurement just by moving the lead over to that input - no button press needed, and it only beeps when there's no current flowing so you can use it to watch a current on the bench but you'll never forget to put the lead back afterwards - they thought it through!)The only downside is you can't measure under 0.8V - that's the cutoff where it starts measuring volts instead of Ohms/continuity.

author: Aldo22
author_rank: Super Contributor
timestamp: December 31, 2024, 10:35:38 am
content: Quote from: Fungus on December 31, 2024, 05:52:25 amNo mV measurement? Really?Then you can't recommend it for electronics.It may be very robust and perhaps well suited for schools or for use in chimpanzee cages, but it's notreallycheap (zt-s4)I don't know why I would buy it.For a similar price, I would rather take an ANENG ST212 or an AN8008. They can do more.

author: Fungus
author_rank: Super Contributor
timestamp: December 31, 2024, 10:44:09 am
content: Quote from: Aldo22 on December 31, 2024, 10:35:38 amI didn't.I said, "If I absolutely had to get a really cheap meter for the people who look at batteries/mains with DT830s".(although itisa fun meter for poking around PCBs to see what you can find - no need to adjust the dial between volts/ohms/continuity)PS: I wouldn't recommend a meter for electronics without uA either, which rules out most Flukes.

author: Aldo22
author_rank: Super Contributor
timestamp: December 31, 2024, 11:36:22 am
content: Quote from: Fungus on December 31, 2024, 10:44:09 amRight, I meant in the sense of “it can't be recommended”Quote from: Fungus on December 31, 2024, 10:44:09 amThat's the point. It's notreallycheap.Maybe there are different prices in different countries, but here, a ZT-S4 costs US $17.53 on ZOYI Official Store (AE) (I could not find ZT-S2 on AE).For that, or for very little more, I get a complete, accurate DMM.I paid US $26.91 for my ZT-225 last August.That's cheap.Quote from: Fungus on December 31, 2024, 10:44:09 am

author: Fungus
author_rank: Super Contributor
timestamp: December 31, 2024, 11:55:05 am
content: Quote from: Aldo22 on December 31, 2024, 11:36:22 amLiterally the first hit for "ZT-S2":https://www.aliexpress.com/item/1005003690881213.htmlThe reason for getting that meter isn't the cheapness though, it's the simplicity (I don't want to say "fool proof" here - there's some ingenious fools out there).If I want acheapmeter I'd get this one:https://www.eevblog.com/forum/testgear/trashy-meters-redux/They're 3.5 Euros plus shipping.

author: Aldo22
author_rank: Super Contributor
timestamp: December 31, 2024, 12:32:40 pm
content: Quote from: Fungus on December 31, 2024, 11:55:05 amAE price comparisons without looking at shipping cost are useless.That's $16.07 shipped. Not cheap for what it is.ANENG ST212 DC/AC clamp meter also does (almost) everything automatically (I don't like that btw.), has a mV range and no A input at all (-> clamp up to 400A, but not accurate below 500mA), NCV, zero line, temp, frequency, capacitance, dual display etc.There is even less that can go wrong.$22.97 shipped.However, current measurement is also unsuitable for electronics. It is good for cars etc.

author: Fungus
author_rank: Super Contributor
timestamp: December 31, 2024, 01:56:31 pm
content: Quote from: Aldo22 on December 31, 2024, 12:32:40 pmI don't know what shipping costs are in your region and it was just the first hit after you said you couldn't find one. Maybe there's a cheaper option.PS: Don't judge "value" by feature set or until you used one.

author: joeqsmith
author_rank: Super Contributor
timestamp: December 31, 2024, 03:02:04 pm
content: Quote from: Aldo22 on December 31, 2024, 10:35:38 amWho is the real chimpanzee here?Electronics is a broad subject. My advice is buy the tools you need.

author: shapirus
author_rank: Super Contributor
timestamp: December 31, 2024, 03:23:32 pm
content: Quote from: Fungus on December 30, 2024, 11:34:22 amIt had nothing to do with the coil in that case. The damaged channel was shorted via the relay's contacts.

author: EEVblog
author_rank: Unknown
timestamp: December 31, 2024, 10:35:33 pm
content: Quote from: joeqsmith on December 30, 2024, 01:48:21 pmThat's generally a deliberate design decision.Try and find a high count bench meter that is as robust as a $50 hand held meter.And it's not because it's bench. The hand held Gossen 6.5 digit 30M is only CAT II rated for example.

author: joeqsmith
author_rank: Super Contributor
timestamp: December 31, 2024, 11:22:13 pm
content: Quote from: EEVblog on December 31, 2024, 10:35:33 pmI wasn't thinking about meters so much as my scope, VNA and SA.Meter wise, if we learned anything from those tests, its that more case does not insure more robust. That $50 Fluke 101 is one of the most robust products I have looked at. It's hard to find any handheld no matter the price, that will compete with it.I may bitch about Gossen's stupidity for not shielding the Ultra but I think their front end is pretty much bullet proof as well.

author: joeqsmith
author_rank: Super Contributor
timestamp: December 31, 2024, 11:31:46 pm
content: Quote from: shapirus on December 31, 2024, 03:23:32 pmSounds like you dug into it. I watched the video and it sounds like Dave never found the root cause. He stated that he was using the relay to short CH1 but had no video of it. If we assume that is correct, did he have enough lead inductance to cause it or is there some sort of sneak path on the other channel driving the coil and the BEMF caused it? I had used some crap power supplies for work once that would go up in smoke during radiated susceptibility testing. The RF would cause the supply to go unstable and the output would swing high enough to trip the crowbar which could not handle the power and would short. Is there enough crap from switching the relay that could have caused it? What were your thoughts about the root cause?

author: shapirus
author_rank: Super Contributor
timestamp: January 01, 2025, 12:05:08 am
content: Quote from: joeqsmith on December 31, 2024, 11:31:46 pmYeah I watched the entire video. At the end of it Dave demonstrated the exact same arrangement that he had in place when CH1 went dead and he could not reproduce the issue after the successful repair. He could not reproduce it when he randomly shorted bare ends of the leads directly by hand, either. The current regulation circuitry in the PSU consistently did its job and dropped the output voltage respectively every time the output was shorted.What was the root cause of the pass transistor failing short initially? I have no idea other than a dodgy transistor (maybe partially damaged with ESD when it was hand-soldered at the factory?)What else could it be? The rest of the components remained the same, nothing else was broken. I don't think it was inductive kickback, either, as there are some protection diodes there close to the pass transistor that are supposed to (I don't know how they're connected, but what else can it be) clamp any overvoltage on the pass transistor's terminals.Was there something radiated by the coil onto the contacts that could cause issues? That sounds too fantastic to me, but I can't disregard it entirely as I do not know everything :).p.s. I've been wondering about the BJT that was getting hot when the blown pass transistor was letting current through when it was supposed to be off. What is its purpose? It's apparently placed after the pass transistor, so can it be there to create load across the output terminals to quickly bleed off any residual charge when the pass transistor is being turned off or partially off? Does that make sense?