Author Topic: Lowest cost True-RMS AC+DC multimeter?  (Read 7440 times)

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Offline iloveelectronics

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Lowest cost True-RMS AC+DC multimeter?
« on: December 14, 2012, 01:23:37 am »
Just doing a bit of research here on True-RMS AC+DC multimeters (not just AC True-RMS). What is the lowest cost meter you know that's capable of this?
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Offline ejeffrey

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Re: Lowest cost True-RMS AC+DC multimeter?
« Reply #1 on: December 14, 2012, 03:19:21 am »
The BK 2712 does this for just over $100.  That is the cheapest one I know of, but I haven't really looked.  Overall I think it is not as nice as the 2709B that was in the $100 shootout, but if DC+AC RMS is a killer feature it might work for you.

Of course, if you want really cheap you can always just measure AC RMS and DC separately and do the math yourself.
 

Offline helloworld922

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Re: Lowest cost True-RMS AC+DC multimeter?
« Reply #2 on: December 14, 2012, 05:26:25 am »
I recently happened upon the Extech EX430 which is on sale for $50 over on Amazon, though RetiredCaps was saying that the probe had horrendous over-shoot. I don't have one so I can't say one way or the other how good or bad it is.
 

Offline iloveelectronics

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Re: Lowest cost True-RMS AC+DC multimeter?
« Reply #3 on: December 14, 2012, 06:28:50 am »
I recently happened upon the Extech EX430 which is on sale for $50 over on Amazon, though RetiredCaps was saying that the probe had horrendous over-shoot. I don't have one so I can't say one way or the other how good or bad it is.

Just checked the specs but it seems that the EX430 only measures True RMS AC, not AC+DC.
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Offline Wytnucls

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Re: Lowest cost True-RMS AC+DC multimeter?
« Reply #4 on: December 14, 2012, 08:05:42 am »
The cheapest one is probably the Uni-T 71A, Franky.
It sells for about USD90.00, plus postage (Chinese sellers on eBay)
You can probably get it for slightly less, directly from China.
It is very good value for money, if one can get past the weak input protection.
Its real CAT rating is probably closer to CAT II 250V only.

Unusual features for a 'cheap' meter:
TRMS AC+DC
Multidata display (3) with one of the best screens in the business.
Dual brightness backlight
Aural warning on the amps range
4~20 mA loop
20,000 count with 2 types of analog bargraph
Sleep mode
USB logging
Peak hold/Max/Min
« Last Edit: December 21, 2012, 05:55:36 am by Wytnucls »
 

Offline mazurov

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Re: Lowest cost True-RMS AC+DC multimeter?
« Reply #5 on: December 14, 2012, 07:15:12 pm »
It depends on what is considered 'true', see this -> http://en.wikipedia.org/wiki/True_RMS_converter  The thermal ones are the best overall, new are very expensive, old ones are aplenty on eBay, HP 3400A,B, 3403C, Fluke 8920, 8921.
« Last Edit: December 15, 2012, 12:21:03 am by mazurov »
 

Offline Wytnucls

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Re: Lowest cost True-RMS AC+DC multimeter?
« Reply #6 on: December 15, 2012, 01:48:48 am »
The thermal ones are not the best overall. They are not very precise and are best used to measure waveforms with high crest factors . They have a low impedance and thus suffer from a high burden voltage.
That's the reason why they have become very rare nowadays.
The old true RMS voltmeters in good condition are not exactly cheap on eBay and AFAIK don't measure true RMS currents.
http://www.ebay.com/itm/Fluke-8922A-True-RMS-Voltmeter-3-5-Digit-/300679690507?pt=LH_DefaultDomain_0&hash=item4601e7f90b
« Last Edit: December 15, 2012, 01:54:13 am by Wytnucls »
 


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