Freaky Amazing DMM?!



Sorry, I didn't pay much attention who I was replying to. I'm not taking sides, but I am saying that high impedance meters are better.
Paul
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In article <31f7ee1b-796f-4a26-a7e4-7755648e2ad2@

Right. It's easy to lower the effective impedance of a high impedance meter. Going the other way is a lot harder.
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Safely, in a dangerous situation? What part of using the right tool for the job don't you understand?
Yes, High-Z meters are good (more useful in more cases), but Low-Z meters have their place too. There simply isn't any argument here, if you need a Low-Z meter, use one. If you need a High-Z meter, use one. "Making do" without the right tool in serious situations is stupid.

Agreed. That's why if you have serious needs you either have a dual purpose meter, with Low-Z and High-Z modes, or you have two meters.
Dave.
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In article <6c4c61b0-5a1e-4425-a47d-0a883437bc57

It's easy to do safely.

What part of understanding electricity don't you understand?

If you're a sparky and all you do is wiring, sure. There is no reason to have a high impedance meter. That doesn't mean that a high impedance meter can't be used safely and accurately.

If you have a meter for every job, sure. If you don't, a little knowledge goes long way.

Nice snip. That's known as a lie in many corners.

No, you understand what you have and use it appropriately. ...something there is an obvious shortage around here.
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After serious thinking krw wrote :

No, you carry the correct tools. You use a load to test for live/dead circuits, not a DMM. (I use test lamps with fuse protected leads). If you need to measure voltage, then you use a voltmeter...how hard is that to understand????
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Re: Freaky Amazing DMM?! Group: alt.engineering.electrical Date: Thu, Jan 22, 2009, 8:01pm (EST+16) From: snipped-for-privacy@gmail.com (Arlowe) After serious thinking krw wrote : In article <31f7ee1b-796f-4a26-a7e4-7755648e2ad2@
Totally useless in areas of high RF. Wrong. That statement simply exposes another large hole in your knowledge and experience. I spent 20 years on a high power HF transmitting station - believe me - I *know* As the man says, the proper tool for the job I would agree. Take two meters. One is 1Kohms. The other is 1Gohms. If the load is low impedance, say 100 ohms, then there's an appreciable error with the low impedance meter-- simple ohms law. While the error associate with the high impedance meter is unmeasurable. People are probably confusing the fact that a high impedance meter while unconnected to anything will pick up signals, for obvious reasons. Paul Sorry, I didn't pay much attention who I was replying to. I'm not taking sides, but I am saying that high impedance meters are better. Right. It's easy to lower the effective impedance of a high impedance meter. Going the other way is a lot harder. No, you carry the correct tools. You use a load to test for live/dead circuits, not a DMM. (I use test lamps with fuse protected leads). If you need to measure voltage, then you use a voltmeter...how hard is that to understand????
=> Goeth ahead then, it is thine arse..Ye can goeth about testing with breakable bulbs [I keepeth them only for quick droplighting]
Whilest others [yon servant included] testeth circuits with one shot deal precision measuring instruments thou canst looketh like a fairytale lightning bug all thou wantest};{)
The Mighty WontVolt
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The Mighty WontVolt formulated on Thursday :

I can read headers...you are Roy...Roy the wannbe. I have seen you around... nobody seems to like you. I understand why.
You don't even know what test lamps are ... I'll explain.. in small words, just for you. 2 incandecent lamps, usually 240 volt 20 watt edison screw lamps connected in series, connected to a pair of fuse protected test leads. I'll even give you pictures: http://www.thew.com.au/pdfs/TMac_LV_Test_Lamps.pdf The proper device for testing for energized circuits.
'effing nutter..
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Arlowe thou truly Ar low..I am not even going to dignify yon blunder with rephrasing...ye are just an arse....let alone bare.
Yon pdf sample pictures and mentation on the subject are a fraud, as ye art entirely fraudulent with yon dull superfluous electrical delusions.
As for ye mentioning The Roy in this thread -
Go fucketh thyself ! ! !
The Mighty WontVolt
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snipped-for-privacy@gmail.com says...>

Sparky, carry crap tools? Ok, you don't need much and evidently can't handle a good tool.
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says...>

Wrong again, in so many ways, but you're good at that. If your field strength is enough to saturate the innards there isn't much that can be done. A low impedance meter isn't going to help. OTOH, we weren't talking about probing inside a microwave oven in operation, rather power distribution panel.

Evidently you don't know much.

Or make the one you have work. It does take some knowledge of basic electricity, but evidently that lets a lot out here.
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Doesn't need to get into the innards directly, you can screen that, but you've got a pair of leads forming an aerial and most likely a diode at the junction of the test lead and the DVM socket. A low impedance input attenuator will load that down to something insignificant compared with what you are measuring.
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says...>

Nonsense. There are many things that can be done to eliminate any external factors. Add a shunt resistor and you have your low impedance meter.

Nonsense. If an input resistor will load down your circuit so will your low impedance meter. It's *exactly* the same thing, except the user gets the choice.
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Go get some practical experience.
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says...>

I certainly have more than you.
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>>>>>>>>
Yes, electricians generally just do just the one similar job. That's why they make meters designed for just such specific purposes. Giving your average electrician say a Fluke 289 is a bit overkill and would likely not be as productive as a more job specific instrument.

That's why many good meters have selectable Low-Z and High-Z modes.
Dave.
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In article <2933ea53-af2a-43a8-86c7-d9e2ec400d99@

>>>>>>>>
That wasn't at issue here. The statement was made that a high impedance meter couldn't be used and that a low impedance *ANALOG* meter was a necessity. It's certainly not true, though one has to understand what one is doing, again a rarity in this group.

Most *good* meters don't. Many sparky meters might.
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Ok, I haven't followed the entire silly thread. From my side I've only been proposing that high impedance meters can be a problem, and the solution is using the right tool for the job.
Dave.
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On Wed, 21 Jan 2009 17:04:38 -0800 (PST), "David L. Jones"

Yes, they can be a problem if YOU DON'T UNDERSTAND WHAT YOU'RE DOING. If you know what you're doing you can get the right reading form a high impedance meter just as well as one that has been crippled by the manufacturer. If necessary, you can cripple it yourself, though that is rarely needed.
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The same with ANY measurement instrument, nothing unique here at all.

Crippled? Hardly the right term, try purposely designed. Just like you wouldn't go around saying a meters DC range is "crippled" because it's 0.5% when they could have made it 0.1%. Or a meters current range is "crippled" because it has a burden voltage of 10mV/mA instead of 1mV/mA. etc.
Usually, with meters, a lower spec is done to meet a lower price point. But in the case in question it is done for the purpose of meeting a (niche) market need. A tool is not crippled just because it doesn't meet YOUR job spec.
Dave.
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In article <0c6126c3-315f-49c2-97b3-
says...>

It is exactly the right term. It is a high impedance meter that has a shunt added to cripple it's input impedance.

If it was a .1% meter with the .5% feature added, yes, it was "crippled".

It does one thing and one thing only. The uncrippled meter will work in a wider variety of circumstances, though we are getting pretty far from the original point.
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