It isn't high tech. But cheap meters don't want to go the extra step. Unfortunately the sorts of folks who have these low end meters are the very ones who lack the understanding of electronics to know the difference. If you or I were in this position, we'd know how to determine if the meter could do it, and how to use a cap to solve the problem. The average buyer of a $2 meter will not know that.
And that's naturally the difference between hobbyists and the educated/professionals.
I have 3 really good bench meters (Fluke and Keithley) which are fully protected against user error and a cheap handheld, the handheld invariably buys it. My most recent handheld is auto-ranging and will protect itself from most errors. It has a fuse for the inadvertent voltage measurement using the ammeter input and range settings. I blew up two of its predecessors. In theory I know what I am doing, but like all humans I occasionally suffer a moment of inattention and pay the consequence.
A good used Fluke handheld bought from a reputable seller might pay for itself in longevity and its ability to survive common mistakes.
Most of my test equipment was bought used on eBay or at local hamfests. The Keithley 2002 was bought new as was the RTX-6001, and a couple of my Tek Scopes.
A good used Fluke handheld bought from a reputable seller might pay for itself in longevity and its ability to survive common mistakes.
Most of my test equipment was bought used on eBay or at local hamfests. The Keithley 2002 was bought new as was the RTX-6001, and a couple of my Tek Scopes.
Last edited:
This is all great stuff.
If only i had a meter to play with
I think I spent about £25 on my DMM.
I read up on it and it was considered decent for its price.
I reckoned it would do me for quite a while, it definitely does a lot more than I can.
I thought it made sense until I knew a bit more about what I want from a meter.
I didn't think to allow for my dopiness. (which I have now discovered is something i would like)
So I was thinking my DMM is repairable. Is it not?
If not, then what sort of price am i looking at for something that protects me against myself?
Sounds like it will earn itself back.
Is there a stock phrase for this protection that I can look out for?
If only i had a meter to play with
I think I spent about £25 on my DMM.
I read up on it and it was considered decent for its price.
I reckoned it would do me for quite a while, it definitely does a lot more than I can.
I thought it made sense until I knew a bit more about what I want from a meter.
I didn't think to allow for my dopiness. (which I have now discovered is something i would like)
So I was thinking my DMM is repairable. Is it not?
If not, then what sort of price am i looking at for something that protects me against myself?
Sounds like it will earn itself back.
Is there a stock phrase for this protection that I can look out for?
Unless it is a blown fuse and it still works on voltage and resistance ranges it is almost certainly beyond repair unfortunately. I have done the same thing, so don't feel too bad.
Generally it will say "protected" or similar and expect to pay a lot more for one of these meters. A Fluke might actually be a good investment.
Generally it will say "protected" or similar and expect to pay a lot more for one of these meters. A Fluke might actually be a good investment.
You can even get a 20 V AC reading out of a 9 V battery, when you have a really cheap meter with just one diode for rectification. It will then indicate 0 V AC when you connect the battery the other way around.
Am I safer getting another cheap one then?
Rather than damage the circuit?
Is that what you mean?
Nope, the fuses are fine.
It doesn't even switch on at all.
Changed the batteries.
I agree.
It can get expensive if I keep doing that.
I am disappointingly unflush currently.
I like the idea of things lasting decades though.
Do the cheaper ones still have the benefits or do I need to be looking above a certain price point?
Looking at some of the prices, I will probably have to go cheap again for now and be more careful.
Are second hand ones worth considering or is it a dodgy area?
What should I look out for please?
So, I would like a DC blocking cap.
A protection against me being a numpty? What is that called? I have seen Overvoltage protection for eg I think.
I am after hand held as I don't have a dedicated desk.
Last edited:
Ah, I see.
I was wondering that, I thought in your previous comment you meant, get a DMM with one in for sure.
Misread.
I don't believe it's possible to learn electronics and not at least blow the fuse by measuring voltage when set to amps. Usually it doesn't take out the meter, but often the DUT (device under test).
I'm going to muddy the water a bit, but it's important to understand a few things about RMS measurements. First, you probably don't need a true RMS meter. When you measure something, always ask yourself what you'll do with the information. When do you ever measure a non-sinusoidal signal and actually need an accurate answer? In my career of 40+ years of designing and fixing electronics the need has only shown up a couple times.
When the need has shown up, I needed the complete RMS result, not what the typical true RMS meter gives you. An RMS result must include any DC on the signal. Otherwise it wouldn't be the equivalent heating value of a DC signal. The normal way you get this with the typical meter is first to measure the DC value. Then you measure the AC value (this assumes the meter AC couples the signal with a capacitor). Then you take those two numbers and do the root sum of the squares. This isn't normally an issue because you're usually dealing with a large AC signal with small or zero DC offset, but it's something that should be understood. A few meters can be switched to include or exclude the DC component, but they're usually big bench meters.
In the past I'd always say, "Buy a Fluke." Today you have some decent options at far better prices so now I say, "If you can afford a Fluke, buy a Fluke." They're still excellent meters, but be sure to get a model designed for electronics, not contractor/HVAC work.
I'm going to muddy the water a bit, but it's important to understand a few things about RMS measurements. First, you probably don't need a true RMS meter. When you measure something, always ask yourself what you'll do with the information. When do you ever measure a non-sinusoidal signal and actually need an accurate answer? In my career of 40+ years of designing and fixing electronics the need has only shown up a couple times.
When the need has shown up, I needed the complete RMS result, not what the typical true RMS meter gives you. An RMS result must include any DC on the signal. Otherwise it wouldn't be the equivalent heating value of a DC signal. The normal way you get this with the typical meter is first to measure the DC value. Then you measure the AC value (this assumes the meter AC couples the signal with a capacitor). Then you take those two numbers and do the root sum of the squares. This isn't normally an issue because you're usually dealing with a large AC signal with small or zero DC offset, but it's something that should be understood. A few meters can be switched to include or exclude the DC component, but they're usually big bench meters.
In the past I'd always say, "Buy a Fluke." Today you have some decent options at far better prices so now I say, "If you can afford a Fluke, buy a Fluke." They're still excellent meters, but be sure to get a model designed for electronics, not contractor/HVAC work.