My “Radio Shack” cheapo didn’t seem to be reading correctly. On reading the manual the clamp section works only on AC. Might be something in particular to check for with these.

Phil

How do you blow a DMM. Don’t they have fuses? I’ve overloaded mine, but just had to replace a fuse. I think they all pretty much have the same standard 10amp fuse,

I have a clamp meter which I think detects DC, but it’s buried since it’s too big for anything I might need it for.

If you’d go by the local auto parts store or junk yard, you could pick up a Ballast Resistor from an old point-style ignition system. You could wire it in series, measure V across it, then compute your I to see if your meter can handle it. That would ultimately be faster than going back to HD…

Replacing the fuses & batteries isn’t hard, but I’ve seen meters that use weird proprietary screw heads. Fortunately I have all those bits, so…

Fuses actually offer suprisingly limited protection. Even the best fast blow fuses take milliseconds to open up, you can fry electronics in microseconds. Exceed the
maximum rating on the input by an order of magnitude (factor of 10), and odds are both the meter and the fuse will be toast.

I've blown four since I've owned my DMM and nothing was harmed. That's the point of having a fuse. I just popped it out and dropped In a new one. I guess there's no knowing what kind of fuses they're using in some of the budget meters, but "Limitron KTK-10" are pretty standard fuses in DMMs. Mine is a Brymen, but I know that the Flukes have standard "Limitron" fuses too. They're pretty standard. I'm pretty sure it would be a waste of money if the fuse couldn't protect your $450.00 Fluke.

Dale uses a clamp meter. Not sure what kind. He might know something.

Build one of these and you won't look back:

http://budgetlightforum.com/node/30693

I have an Amprobe clamp on at work that I use, but way out of the range for me to buy off the shelf. I use one piece of 12 Ga multistrand copper that I cut at 5” long to maintain consistency during measurements. I will be interested to see what pops up here for budget options.

PD68 wrote:

ImA4Wheelr wrote:

Build one of these and you won’t look back:

http://budgetlightforum.com/node/30693

I swear I’ve read that thread 20 times over the last couple years, and I just don’t get it. Also it’s clear I need a reliable meter to tune in the new shunt, which I do not have.

I used a bench top variable power supply to make mine.   I don't know how accurate the meters on it are, but it's all I have to go by.  I just cut a 6" 14ga wire with an inch of insulation stripped from each end.  I then put the wire in the power supply and then ran 10amps of current through the wire.  I then probed for the spots that gave me 10mV.  I then soldered wires to spots just a tad wider than those spots because the solder reduces resistance a tad.  You can then tune the wire be either notching the wire or adding solder.  You have to let the wire cool from soldering before testing it for accuracy.  

My version, banana sockets are to plug a multi-meter (set to mV range):

22 AWG wire for shunt, about 8” gives 10 mohm (so 10 mV/A). Trim exact length by using an amp meter in series with the shunt and a voltage source. Going over 10A you should probably use thicker wire and lower resistance for the shunt, as per the linked thread above.

Note that copper wire has a relatively high tempco re. resistance. There will be a 4% change in shunt resistance with every 10 C change in temperature. Proper shunt/resistance wire is manufactured from alloys with much lower tempcos.

Dimbo The Blinky wrote:

If you’d go by the local auto parts store or junk yard, you could pick up a Ballast Resistor from an old point-style ignition system.

These are made with Nichrome wire where the resistance increases as the wire heats so I wouldn’t go there. They will handle a lot of current though, just not accurately until the temperature settles down. These were used to compensate for lower battery voltage while the starter motor operated, then lowered current afterward to make the coil and contact points last longer.

Phil

pilotdog68 wrote:

I sent a rather low-ball offer on this model, we’ll see what he says.

http://pages.ebay.com/link/?nav=item.view&id=331686413279&alt=web

was undecided between that 210E (24-28 USD) (because of the 1mA resolution, I prefer precision for what i do than 500+ Amp capability), the Mastech MS21080-35 USD (the cheaper 2108A version has not TrueRMS and no Inrush current 27-30 USD) but in the end I opted for a 216C for no reason…. (as always), well the reason was mainly because it seemed a bigger discount even if i ended spending more of what i had planned…47 euros shipped tskk . Always speaking of DC current clamps

It was able to detect 8mA (the clamped displayed 0.01A) And testing various low currents with my linear variable PSU i got very very decent results
But somehow i was not able to measure the battery drain of my sister Toyota Yaris with headlights on, I whink they should absorbe near 9Amp, dunno why

Instead , don’t know if it was reliable for instantaneous DC current (because it calculates the inrush current doing the Fourier transfor of a variable current) i was able to measure 466 Amp from the same yaris D4D to start the engine (battery rated for 570Amp cold start, so it could well be)

If you need me to check something just ask, i’ll do what i can while i’m not at work

I was also looking for one last year too. My budget is enough for Uni-T only. 210E seem to be a good choice for measuring Amp consumption for flashlight. 211 cost almost double of 210.

Well even if you need to measure AC.. Until it’s a standard sine wave like our common AC we have at home… You are really ok.

Truerms is something I probably never come to use since it’s used for different waveforms.

If you look at your dmm at home you will notice it will measure AC but it’s not trueRms…

I took the 216C mainly for the inrush function… The trueRms it’s a plus… If it is real lol

Yes the zero function is something you have to look for. Because usually clamp do add some offset in the value because of environmental factors and other stuff. So, zeroing will put the displayed value to zero, before you take a measure. Some clamps do not have the zero button but once you go back to a different setting and forth to the AC they “self zero-ed” themselves… So just look for a YouTube video… Or even better search for a review in a competent site like eevblog or such.

The inrush is used for AC measurements (at least in mine) and in simple terms measured something similar to the peak current in its first 100ms(in mine model).

So for example you can set the clamp to inrush mode leave it there alone and go powering up a system, go back to where you left the clamp and see the absorption peak of the system while it started.

I think it differs from the simpler peak because after it has monitored something when firstly the current arrive it stores the data and not continues to monitor for a higher value.
Also the calculated current should be done by an integral and not just by looking for the highest value… This could be bull@hit from my imagination I’ve should have read them somewhere but I’m not sure… So if you want you have to research and scrutinize better

Hopefully I made myself understandable, sometimes I read what I wrote few minutes earlier and I can barely understand it myself… Lol

We could definitely do that If we could all agree to one or two model? 

pilotdog68 wrote:

Can your wizardry get us a fantastic deal on the 210e?

Primary use of the clamp is for flashlight measurement and serve as a back up DMM at the same time? Which models are worth considering? 

https://en.wikipedia.org/wiki/Inrush_current.  

pilotdog68 wrote:

I'm really not even sure what "inrush" is. I've seen some discussions about "zeroing" vs "relative" but I'm not sure if that's something I need to look out for

I think if you have to be on the 28-38 use budget and have DC current (for flashlights obviously) there are not many models and a lot are just rip off of the one I mentioned earlier

Shouldn't be difficult to get 201E under $30.  Any more takers?

Yes, it was my first choice, but remember, I’m a hobbyist so asking to me is like asking to a buddy.
Anyway I’m really curious to see the GB price if this will received the due attention. Too bad I already spent more than what I needed