My first multimeter

#12

Joined Nov 30, 2010
18,224
I wasn't the one who recommended Fluke, but the answer is that Fluke has a reputation for making quality meters. You pay for that.
I disagree. I paid for a meter that has not broken or needed calibration for 38 years. All the switches work like new. All the features work like new. I call that paying for, "performance" instead of paying for, "reputation".
 

kyu9971

Joined Mar 28, 2015
90
Best wishes for retirement and for your new hobby .
I will begin by a simple and economic advisers .
you'll have time to increase your equipment and experience .
kyu9971
 

ian field

Joined Oct 27, 2012
6,536
I watched a YouTube video yesterday where the narrator re-calibrated a Harbor Freight DMM! A non-calibratable DMM. He adjusted a potentiometer. I don't need a DMM that will read to 4 or 5 decimal places. A handheld meter that will read to 2 or, at the most, 3 decimal places is fine with me. 2 or 3 decimal places is accurate enough for me.

Why do you keep touting Fluke meters? How does Fluke justify charging hundreds of dollars for a basic meter? Surely, there are meters as good as Fluke, but that cost less.

What is an LCR meter?

You guys are helping me narrow down my brand choice for a DMM. Made in America, of course!
My first ever DMM - a cheap Chinese one, was fished out of a bin where I worked at the time.

The ACV and Ohms ranges were dead, so I opened it up and had a look. aside from the LSI chip there was a 8-DIL dual op-amp. Taking the easiest option I replaced it - lo and behold, the missing ranges were back.

There was a preset pot on the PCB, and in due course I was able to borrow a recently certificated AVO8 to adjust it with.

That meter served me well for a good few years, it got relegated to the shed a few years back when I bought something a bit more up to date.

Actually, I keep it indoors - but its the one that gets used when I need a DMM in the shed.
 

Thread Starter

Macnerd

Joined May 22, 2014
67
Do you guys know anything about Amprobe meters? Their website doesn't give prices. I tried to contact them by e-mail, but there's a 100 character maximum!
I wish to ask more questions. I'm sorry that I'm asking so many questions. The more questions that I ask, the more I learn & the better I can narrow down my choice of meter.
The specs that I've seen on the maximum resistance reading of the meters tops out at 60 megohms. Surely, there are resistors with more than 60 megohms of resistance. How does one measure a resistance that's higher (or lower) than the maximum (minimum) on the meter?
Likewise, how does one measure a capacitance that is higher or lower that the maximum/minimum on the meter?
There are references in these posts to LCR meters. Better meters measure inductance. Why get an LCR meter when one can buy a multimeter that measures inductance?
 

shteii01

Joined Feb 19, 2010
4,644
Do you guys know anything about Amprobe meters? Their website doesn't give prices. I tried to contact them by e-mail, but there's a 100 character maximum!
I wish to ask more questions. I'm sorry that I'm asking so many questions. The more questions that I ask, the more I learn & the better I can narrow down my choice of meter.
The specs that I've seen on the maximum resistance reading of the meters tops out at 60 megohms. Surely, there are resistors with more than 60 megohms of resistance. How does one measure a resistance that's higher (or lower) than the maximum (minimum) on the meter?
Likewise, how does one measure a capacitance that is higher or lower that the maximum/minimum on the meter?
There are references in these posts to LCR meters. Better meters measure inductance. Why get an LCR meter when one can buy a multimeter that measures inductance?
http://www.amazon.com/s/ref=sr_st_p...PROBE+Digital+Multimeters&sort=price-asc-rank
 

IcedFruits

Joined Jan 15, 2014
100
Do you guys know anything about Amprobe meters? Their website doesn't give prices. I tried to contact them by e-mail, but there's a 100 character maximum!
I wish to ask more questions. I'm sorry that I'm asking so many questions. The more questions that I ask, the more I learn & the better I can narrow down my choice of meter.
The specs that I've seen on the maximum resistance reading of the meters tops out at 60 megohms. Surely, there are resistors with more than 60 megohms of resistance. How does one measure a resistance that's higher (or lower) than the maximum (minimum) on the meter?
Likewise, how does one measure a capacitance that is higher or lower that the maximum/minimum on the meter?
There are references in these posts to LCR meters. Better meters measure inductance. Why get an LCR meter when one can buy a multimeter that measures inductance?
You sir, are thinking a lot, just get something like this model - they give accurate enough readings for hobby level: http://www.amazon.com/s/ref=sr_st_price-asc-rank?keywords=dt9205a&qid=1430684057&rh=n:16310091,k:dt9205a&sort=price-asc-rank
Please use one for few days then decide where to spend for a good one. Having 2-3 Multimeters is not a bad idea at all.

The Harbor Freight one seems to be cheapest model 830B, they fetch a bit more current for measuring and give much deviated readings at weak voltages. I have one of these, opened it up many times, and found there is no opamp on the circuit board. Well, that was my observation, anyone here checked if all these models are like this ? I would recommend these for casual measurement purposes, not for calculation purposes.

:)
 

#12

Joined Nov 30, 2010
18,224
How does one measure a resistance that's higher (or lower) than the maximum (minimum) on the meter?
Likewise, how does one measure a capacitance that is higher or lower that the maximum/minimum on the meter?
You don't. Now, where is it that you need to measure more than 60 megohms?
 

dl324

Joined Mar 30, 2015
18,326
Surely, there are resistors with more than 60 megohms of resistance.
That won't be a factor for more than 99% of the measurement's you make.
Likewise, how does one measure a capacitance that is higher or lower that the maximum/minimum on the meter?
You devise an alternate method to measure.
There are references in these posts to LCR meters. Better meters measure inductance. Why get an LCR meter when one can buy a multimeter that measures inductance?
Multimeters measure L and C at a fixed frequency. I personally go decades between needing to measure L or C. I seldom cherry pick values; I prefer to factor tolerance into my designs.
 

kyu9971

Joined Mar 28, 2015
90
my tool comes at 2 megaohms , which I use to see if an appliance has an earth leakage .
An multimeter that comes at 60 megaohms ( although there ) I not think is good for start.
 

WBahn

Joined Mar 31, 2012
32,834
Do you guys know anything about Amprobe meters? Their website doesn't give prices. I tried to contact them by e-mail, but there's a 100 character maximum!
I wish to ask more questions. I'm sorry that I'm asking so many questions. The more questions that I ask, the more I learn & the better I can narrow down my choice of meter.
The specs that I've seen on the maximum resistance reading of the meters tops out at 60 megohms. Surely, there are resistors with more than 60 megohms of resistance. How does one measure a resistance that's higher (or lower) than the maximum (minimum) on the meter?
Likewise, how does one measure a capacitance that is higher or lower that the maximum/minimum on the meter?
There are references in these posts to LCR meters. Better meters measure inductance. Why get an LCR meter when one can buy a multimeter that measures inductance?
What is SO objectionable to just getting a cheap, <$10 meter and using it for a while until you have a reason to get a better meter (most likely that reason will never come)?
 

Thread Starter

Macnerd

Joined May 22, 2014
67
AHA moment!
Now I understand the difference between accuracy & precision!
Precision is the number of decimal places after the zero & accuracy is +/- whatever percent. I've seen accuracy of +/- less than 1% on sub$100 meters. What do you recommend that I look for? +/- 0.5%, +/- 0.3%, +/- 0.75%? Price-wise, I'd like to keep it under $100. Under $50 would be even better. I definitely want True RMS. I definitely don't want averaging.
 

WBahn

Joined Mar 31, 2012
32,834
Accuracy is how close the measured value is to the correct value. Precision is how repeatable the measurement is. The number of digits displayed places limits on both but is a measure of neither.

Let's say that you measure a voltage that is exactly 1V (for discussion sake) and you use a meter with 10 digits after the decimal point. You make five measurements and you get:

0.7652839549
1.1987492959
1.264839784
0.8263740190
1.0933829551

You have a meter that is neither very accurate nor is it precise.

Now you take another meter and get the following measurements:

1.2384756184
1.2384756192
1.2384756188
1.2384756182
1.2384756186

You have a meter that is very precise, but is not very accurate.

0.9968730921
1.0042878407
1.0033309786
0.9982374019
0.9971160228

Now you have a meter that is pretty accurate, but not very precise.

In most situations, I'll take precision over accuracy, if for no other reason than that I can calibrate for accuracy, even if it's just an index card with a bunch of calibration values written on it, whereas there is very little you can do for lack of precision (averaging many measurements is about the only way to address it and that is not always an option).
 

WBahn

Joined Mar 31, 2012
32,834
AHA moment!
Now I understand the difference between accuracy & precision!
Precision is the number of decimal places after the zero & accuracy is +/- whatever percent. I've seen accuracy of +/- less than 1% on sub$100 meters. What do you recommend that I look for? +/- 0.5%, +/- 0.3%, +/- 0.75%? Price-wise, I'd like to keep it under $100. Under $50 would be even better. I definitely want True RMS. I definitely don't want averaging.
Why do you definitely want True RMS? What will you be doing that justifies the added expense (though the price differential is no where near what it used to be).

At least you are classifying it as a "want" and not a "need".
 

WBahn

Joined Mar 31, 2012
32,834
In looking at the accuracy ratings, don't forget to take into account whether it is a percent of reading or a percent of full scale. Also, particularly if it is a percent of reading, there will usually be an additional error limit indicated as a number of digits in the last place. That can make a lot of difference in how good it sounds versus how good it is.
 

wayneh

Joined Sep 9, 2010
18,104
In most situations, I'll take precision over accuracy...
Me too. Accuracy should always be questioned anyway, regardless of how good the meter is. You always have to ask, does this reading make sense? Am I measuring an artifact?

But if the reading won't hold steady or you can't get the same reading repeatedly, it'll make you crazy. For what it's worth, the precision of the cheap meters is quite good. I take for granted that the accuracy isn't great, but whatever they lack in accuracy is not an issue for home or hobbyist work.
 

WBahn

Joined Mar 31, 2012
32,834
Me too. Accuracy should always be questioned anyway, regardless of how good the meter is. You always have to ask, does this reading make sense? Am I measuring an artifact?

But if the reading won't hold steady or you can't get the same reading repeatedly, it'll make you crazy. For what it's worth, the precision of the cheap meters is quite good. I take for granted that the accuracy isn't great, but whatever they lack in accuracy is not an issue for home or hobbyist work.
Fully concur!
 

Thread Starter

Macnerd

Joined May 22, 2014
67
The light appears to be getting brighter.
Absolutely. I'm starting to see the light at the end of the tunnel. Just my luck, someone will turn off the light!
Sorry about that, but I have some more questions.
I've watched YouTube videos, & some meters have 9V batteries & some meters have 2 AAA or 2 AA batteries. The narrator says that 9V batteries don't last as long as 1.5V batteries. I would think that 9V batteries would last longer than 1.5V batteries. Is it just the opinion of the narrator that 9V batteries don't last as long? Is that something that I should look for? What is that the consensus of opinion of the moderators regarding 9V vs 1.5V?
Some meters have an AC bandwidth specification. What is that? As a hobbyist I probably shouldn't concern myself with that, right?
So, I'm narrowing down my brand choice. I'm retired & living on a fixed income. I don't want to spend $400 on a Fluke meter. So, I have to choose a meter that has the features that I want & the precision & accuracy that's within my budget.
 

wayneh

Joined Sep 9, 2010
18,104
The cheap meter runs for years on its 9V battery, with intermittent use. That's with the el-cheapo battery that comes with it. I don't have any I've used long enough to wear out the replacement battery.

It is true that 2AA batteries contain more energy than a 9V battery, so with heavy use it could be true that they would last longer. But I don't think something you do once a year should have much bearing on your choice.
 

dl324

Joined Mar 30, 2015
18,326
I'm starting to see the light at the end of the tunnel. Just my luck, someone will turn off the light!
Be careful, it might be a train.
I've watched YouTube videos, & some meters have 9V batteries & some meters have 2 AAA or 2 AA batteries. The narrator says that 9V batteries don't last as long as 1.5V batteries.
Well he's probably right. The last time I checked 9V battery specs, they were rated under 100mAH; so you've got around 1 watt hour. NiMH AA cells are now around 2.5AH, so you get 3 watt hours of power. Simple arithmetic.
I would think that 9V batteries would last longer than 1.5V batteries. Is it just the opinion of the narrator that 9V batteries don't last as long?
No, your intuition is wrong.
Is that something that I should look for? What is that the consensus of opinion of the moderators regarding 9V vs 1.5V?
No. Use rechargeable batteries and recharge when they run down.
Some meters have an AC bandwidth specification. What is that? As a hobbyist I probably shouldn't concern myself with that, right?
Depends on what AC signals you intend to measure. If you're going to measure line frequency AC, it's a don't care. If you're planning to measure RF frequencies you still don't care because you should be using a frequency counter. Even as an electronics hobbyist, you should use the correct tool for the job. If all you have is a hammer, you start treating everything like it's a nail...
I'm retired & living on a fixed income. I don't want to spend $400 on a Fluke meter. So, I have to choose a meter that has the features that I want & the precision & accuracy that's within my budget.
The general consensus has been to get a free Harbor Freight meter and buy a "better" one when your needs outgrow it. You may find that you'll be able to go for many years with a simple, inexpensive meter. I went for decades with my RCA analog meter and a homemade voltmeter. But then again, I started at a time when equipment was expensive; so, in addition to my digital voltmeter, I made my first couple of power supplies and signal generator (rectangular waves only). Now things are so cheap you can buy anything you really need; but, at the same time, you don't learn about their inner workings...
 
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