Oh, and if you know where to look… Harbor Freight ALWAYS has a 20% off coupon available. Yes, you can combine it with the sale price when the meter goes on sale. The last time I picked up a few of these, I paid $29.99 - 20% = 23.99 each. For the price, I leave these things eveywhere… Garage, basement, back shed, in the car… I can’t tell you how many times having a meter comes in handy…
You can get a $82 meter for $36 plus shipping. Autoranging is helpful when for example you are checking car battery voltage, and then want to check flashlight battery voltage. You don’t have to remember to change the range.
My old Radio Shack DMM with manual ranging has a DC volt range of 3 volts, and the next range is 30 volts. So I could not even check Nimh batteries at 1.2 vots and Li-ion batteries at 4.2 volts without changing the range. It can be done, but who wants to?
I’ve had cheap manual range meters in the past, and some of them are even still working, but auto ranging is more convenient.
I really like my Amprobe AM-520 for a DMM that’s not too expensive. Amazon seemed to have the best prices at the time I purchased it. The also have the AM-510 for a few bucks less, which seems to be very similar with just one or two feature left off. It looks and feels solid, not like a cheap meter.
I also like my Fluke FM27, but prices on them have jumped up since the cheap government surplus sources on ebay have dried up. They are super rugged meters that were originally built for military use,
Uni-T seems to get generally OK reviews, but there are enough differences between models so try to find reviews on the specific one you want. Vichy seems to get slagged in some reviews for poor build quality.
Edit: I just looked at the link for the Ideal meter on ebay, it looks like a good deal for all the features it has.
FWIW, my old DMM died last month so I replaced it… with an Equus 3320 (as recommended above). It was the best low-price DMM I could find on Amazon in a single afternoon. It lacks many of the extra / nonstandard features in the more expensive DMMs, but it’s a great budget item with all the basics and a couple relatively simple extras. I’ve used it quite a bit in the month I’ve had it, and am very happy with it.
Well my Extech EX330 arrived today. I like it, but the only thing it offers over the free DMM I got from CircuitSpecialists.com is auto ranging and being able to read current at a higher resolution. I should have read the user's manual for the EX330 instead of just the datasheet, as the accuracy +- is worse than I thought. Have no way of actually testing it though (don't have a reference voltage).
What confused me on my existing DMM is that switching from 10A down to mA or uA would cause different readings. Same thing with the new DMM. It seems as though the lower you go the more resistance there is, so that impacts the readings. So for example 500 mA on the 10A setting might be 300 mA on the mA setting. I have to know that once the current draw goes above 400 mA, the mA setting won't be accurate.
I was able to successfully measure PWM in kHz, despite it being about .2 kHz slower than what I calculated it should be (9.2kHz instead of 9.4, and 2.2 instead of 2.4).
I attempted to measure 7135 leakage current, but I'll have to save that for another day when I can do a little more formal testing.
You’re correct on all accounts. The meter is really measuring a voltage across a shunt resistor in order to tell you current flow. In order to generate the more precise (probably an extra digit) numbers on the lower setting, it uses a larger value shunt resistor. If you have another working meter, you can actually measure the resistance of the new meter in the two different ranges.
Here’s where it gets tricky. It’s probably quite accurate in both settings. When set to the 10A setting, it uses a low value current shunt so 500mA flows and it tells you this. When set to the mA setting, it uses a higher value current shunt so only 300mA flows, and it also tells you this.
The reading is accurate in both cases - its just that the meter’s effect on the circuit is different.
If you don’t need super high resolution - when it comes to flashlights, the meter will always be closer to reality in the 10A range. You’ll be missing a digit, but you’re limiting the effect of the meter on the circuit.
So I finally got sick and tired of waiting for the Harbor Freight meter (rebranded Mastech MS8229) to go on sale and just bought it (with 20% off coupon of course). It's my first auto-ranging meter and it can be set to manual ranges. The tilt proper-upper thingie is kind of cheap. The meter doesn't scream quality, nor does it seem real bad. My first one though wouldn't hold the COM lead tight; the lead would just pop right back up out of it. I only noticed it with my homemade test leads (my banana plugs don't have the plastic shroud that the stock leads have). So I had to take it back and swap it for another one (and the first "other" one I picked up had the same problem with the voltage lead jack - I took my leads in with me to test). So be warned, check the jacks for a tight fit before leaving the store!
Oh, I did use the first meter last night for some readings. I got 2.83A on a Nanjg 105C 2.8A driver (with my homemade leads, I forget what it was the stock leads)!
Wow! You must have ESPN or something! So what did you think of your Uni-T in comparison to the HF meter? (It's nice that the HF meter isn't sealed up and at all and you can open the box and fiddle with it.)