Author Topic: EEVblog #1067 - Analog vs Digital Multimeters  (Read 19279 times)

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Offline Fungus

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Re: EEVblog #1067 - Analog vs Digital Multimeters
« Reply #175 on: April 03, 2018, 04:58:18 pm »
We fall into the excess because:

1) with safety glasses + face shield, vision is very small

2) the insulating gloves were very thick and did not allow to hold the probes correctly, nor to make gestures of precision.

So, over-protection may increase the risks of accidents, which is a mistake.

Take a copy of the FAQ along next time:
Quote
Can all employees just dress in category 4 PPE when working on energized equipment?

Working in Category 3 or Category 4 PPE can be hot, difficult and result in loss of dexterity and vision. Some workers argue that while working in Category 4 PPE provides them more protection in the event of an accident, they are more likely to make a mistake and cause and accident when wearing Category 4 PPE.
« Last Edit: April 03, 2018, 05:03:09 pm by Fungus »
 

Offline oldway

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Re: EEVblog #1067 - Analog vs Digital Multimeters
« Reply #176 on: April 03, 2018, 05:42:42 pm »
Yes, I agree, but in companies in the chemical or petrochemical field, as a subcontractor, there is no possibility to discuss .... You do what they ask you or you are forbidden to enter factory the next time.

And we must also ask ourselves other questions: what are the real risks? Is a 120V 50ah battery a "high energy circuit"? Not in my opinion anyway.
 

Offline bd139

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Re: EEVblog #1067 - Analog vs Digital Multimeters
« Reply #177 on: April 03, 2018, 05:53:53 pm »
High energy really depends on the source impedance if you ask me. Compare a capacitor to a battery bank for example.

As for electrical safety if you’re subcontracted or an employee it’s not your decision to make potentially. So if you blow yourself to bits or even worse a colleague, bye bye insurance claim.
 

Offline oldway

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Re: EEVblog #1067 - Analog vs Digital Multimeters
« Reply #178 on: April 03, 2018, 06:17:31 pm »
In terms of responsibilities, it was always clear to me that I had to respect the safety rules imposed by my employer, not the exaggerated ones of some of his clients
In case of an accident, it seems to me that it would be the insurance of my employer that would intervene.
 

Offline floobydust

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Re: EEVblog #1067 - Analog vs Digital Multimeters
« Reply #179 on: April 03, 2018, 06:47:22 pm »
Here's a more modern analog meter. CAT III, 600V. It even has a neck strap so you can hang it close to your vital organs:

It's got no approvals, just a misleading fake claim by Kyoritsu.
"designed to" does not mean it went through formal (61010) assessment.

I recall you can see creepage/clearance violations on the pcb for that meter, it would not pass
 

Offline Fungus

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Re: EEVblog #1067 - Analog vs Digital Multimeters
« Reply #180 on: April 03, 2018, 06:54:58 pm »
"designed to" does not mean it went through formal (61010) assessment.

Good point. That's pure weasel wording, I should have spotted it.

Still: It supports the theory that they only make those analog meters for the die-hard curmudgeons. If you turned up at a real job with one of those they'd probably kick you out in favor of the guy behind you who's waving a yellow DMM.
« Last Edit: April 03, 2018, 07:02:05 pm by Fungus »
 

Offline Fungus

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Re: EEVblog #1067 - Analog vs Digital Multimeters
« Reply #181 on: April 03, 2018, 07:05:10 pm »
I bet they make the apprentices wear one of those suits to change light bulbs.  :popcorn:

 

Offline floobydust

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Re: EEVblog #1067 - Analog vs Digital Multimeters
« Reply #182 on: April 03, 2018, 08:34:40 pm »
The Fluke DMM recall where they spontaneously rebooted due to EMI when connecting probes to HV. You wouldn't have that problem with an analog VOM.
The ghost voltage readings due to high input impedance, analog VOM usually not misleading there. Any electrician who has been mislead, just sticks with the multimeter that is truthful for them.

 

Offline bd139

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Re: EEVblog #1067 - Analog vs Digital Multimeters
« Reply #183 on: April 03, 2018, 09:02:55 pm »
Try keying a 100W RF amp next to your analogue meter. Swings a bit ;)
 

Offline G7PSK

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Re: EEVblog #1067 - Analog vs Digital Multimeters
« Reply #184 on: April 03, 2018, 09:15:24 pm »
 

Offline bd139

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Re: EEVblog #1067 - Analog vs Digital Multimeters
« Reply #185 on: April 03, 2018, 09:21:12 pm »
Yes that's designed for that and is appropriately shielded. If you look at the SWR bridge or load in those things, it's usually in a separate compartment.

Also, fuck me that's expensive.  You can get the same damn thing for 70 quid from ML&S: https://www.hamradio.co.uk/accessories-swr-power-meters/mydel/mydel-swr-006-meter-pd-6634.php
 

Offline G7PSK

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Re: EEVblog #1067 - Analog vs Digital Multimeters
« Reply #186 on: April 03, 2018, 09:38:37 pm »
Was not thinking of buying it,RS tends to be very expensive it was just the first hit for an RF meter. Never really noticed a meter twitching from RF but have had digital ones and other forms of digital display go crazy from just a few watts of RF.

I once saw a fluke get blown up when exposed to the HF on a tig welder, but that machine used to leak HF back up into the mains and no electronic equipment could be used on the same circuit, real beast of a late 1950's machine.
 

Offline PA4TIM

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Re: EEVblog #1067 - Analog vs Digital Multimeters
« Reply #187 on: April 03, 2018, 10:01:13 pm »
A quick search for (non existing ? ) Cat rated analog  Intrinsically Safe multimeters (The red Flukes are made for this category)
https://www.gossenmetrawatt.com/english/produkte/metraport3a.htm
https://www.tequipment.net/Simpson260-9SP.asp?rrec=true
https://www.test-meter.co.uk/dilog-pl001-analogue-multimeter/
https://www.tester.co.uk/extech-38073a-analogue-multimeter
https://uk.rs-online.com/web/p/analogue-multimeters/0219434/
https://www.tester.co.uk/dilog-pl001-analogue-multimeter
https://www.rapidonline.com/voltcraft-vc-2030a-analogue-multimeter-64-3344
https://www.amazon.de/Analog-Multimeter-10-A-AC-DC/dp/B006KCP2M8/ref=pd_lpo_vtph_107_lp_tr_img_2/258-5550937-2550932?_encoding=UTF8&psc=1&refRID=ZXTGPT70ZZJHSH64WVZ3
https://www.amazon.de/VOLTCRAFT-Hand-Multimeter-analog-VC-5080-Kalibriert/dp/B00Q2VV22Q/ref=pd_sbs_107_4?_encoding=UTF8&psc=1&refRID=R8NVRV50B5G581D8WDA2
https://uk.rs-online.com/web/p/analogue-multimeters/4248903/

I can not find it anymore but I did see a video a 2 years ago about some power electronics stuff in industry. I was looking for info about trip-units (those 50 kilo "fuses")  I noticed all the guys in that video used analog meters, it had something to do with safety.

I have around 30 analog meters, I collect them. The only ones I really use are a Fluke 845 and a HP-4329A, the rest is on display in the living room and I use them so now and then for fun. For work and hobby I only use digital multimeters. My main meter is a Keithley 2000, cat rating ?? I still live  ^-^

Are analog meters dangerous ? Bullshit, the display has nothing to do with safety. The fact they follow the way of the dodo and sliderule had nothing to do with safety or cat ratings. Only with comfort and more resolution.

I have seen digital meters go on tilt from 80W RF, the laptop crashed too

The best safety is to use that grey mass between your ears. 

I think most DMM's produced are not very safe at all.  All that cheap Chinese crap 90% of the forum users here adore and use. For safety I rather use an AVO 8 with the original test leads as some 30 dollar piece of crap (or one from the huge list unsafe meters here on the forum). with fake ratings and fake fuses (if it has a fuse)

Just something that came to mind. Is a meter with a separate current input so much safer ?
If I measure current and forget to insert the probes back to the voltage input and still try to measure a voltage I have a problem.
If I have a combined jack and want to switch from current to voltage there is less chance it goes wrong. If I forget to swiths the voltage I have a problem in both cases. But if I forget to put the probe back to the voltage socket...oh wait, that does not matter if there is only one bus  >:D
« Last Edit: April 04, 2018, 06:12:43 am by PA4TIM »
www.pa4tim.nl my collection measurement gear and experiments Also lots of info about network analyse
www.schneiderelectronicsrepair.nl  repair of test and calibration equipment
https://www.youtube.com/user/pa4tim my youtube channel
 
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Offline Fungus

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Re: EEVblog #1067 - Analog vs Digital Multimeters
« Reply #188 on: April 04, 2018, 12:19:08 am »
I can not find it anymore but I did see a video a 2 years ago about some power electronics stuff in industry. I was looking for info about trip-units (those 50 kilo "fuses")  I noticed all the guys in that video used analog meters, it had something to do with safety.

If it was high voltage stuff they might have been using specialist voltmeters.

(which look like analog multimeters, but aren't).
« Last Edit: April 04, 2018, 10:49:38 am by Fungus »
 

Offline oldway

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Re: EEVblog #1067 - Analog vs Digital Multimeters
« Reply #189 on: April 04, 2018, 08:01:40 am »
@PA4TIM: I know you for a long time, including the forum circuit online and I know you have no experience or qualifications to talk about safety in high energy circuits.

You are radio amateur, collector, passionate to the extreme by the electronics, a brilliant electronic self-taught people who lives for and by the electronics.

You talk about security thinking about the measures you do every day at home, in your workshop ...... And here I agree with you, I too have an AVO 8 and there is no problem to use it in a 230V circuit protected by a 25A circuit breaker .... These are low energy circuits with a short circuit current of 2000 to max 5000A

In case of an accidental short circuit, there is nothing more serious to expect.

In the discussion, there was talk of using such devices on high energy installations with short circuit currents of tens of thousands of amperes.

In these cases, the consequences of a short circuit are quite different, they can even be lethal. (see videos)

The advice never to use analog multimeters to make measurements on high-energy circuits is a generalization based on the observation that 99% of the analog multimeters currently still existing are either old cat unclassified devices or the worst crap multimeters sold at 10 bucks.

There are indeed some modern analog multimeters duly protected and cat rated, but they are a tiny part of what still exist.

Of course, you can only trust in in high quality and famous brand as well for analog multimeters than dmm.


EDIT: As BD139 pointed out, using a measuring device that does not have a cat classification or does not have the correct cat for the work you are doing is a serious professional misconduct and the insurance might not intervene in case of accident.

EDIT 2: Let us remember that pure analog multimeters (without electronic circuit added) are NEVER AC true rms even if they cost more than 400 bucks and are useless for AC measurements with  PWM inverters.
« Last Edit: April 04, 2018, 12:22:47 pm by oldway »
 

Offline mikerj

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Re: EEVblog #1067 - Analog vs Digital Multimeters
« Reply #190 on: April 04, 2018, 09:18:39 pm »
I still use my ancient Micronta FET input analog meter fairly regularly.  Sometimes seeing how a value is moving is more important than measuring it to 3 D.P.s.

Have you actually watched the video? The part where Dave shows that most bargraphs in digital multimeters (well, at least those shown in the video) are both faster (no mechanical inertia) and more accurate in displaying value changes and fluctuations?

The fact that a mechanical movement provides a degree of integration is actually preferable IMO.  You can't watch really fast moving signals on either, you need a scope for that, but if you have e.g. a noisy signal with a varying DC level a bargraph can be pretty hopeless.  It's also a personal thing, having used analog multimeters for years I simply prefer them to digitised bargraphs.
 


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