New TRMS Uni-T UT139C DMM is available now

[lpc32]

1. Burden voltage: https://www.eevblog.com/forum/testgear/new-trms-uni-t-ut139c-dmm-is-available-now/msg289230/#msg289230
2. Accuracy beyond what's indicated in the manual?
3. Continuity is pretty fast.

[mmatic]

1. Burden voltage: https://www.eevblog.com/forum/testgear/new-trms-uni-t-ut139c-dmm-is-available-now/msg289230/#msg289230
2. Accuracy beyond what's indicated in the manual?
3. Continuity is pretty fast.

Hi!
Do you maybe own ut139? Does this multimeter has better current accurancy that ut61e?

Best Regards Matic

[Lightages]

I have had both and the UT61E  is rated more accurate of course but my UT139C is as accurate from my recollection.  It doesn't mean it will stay that way but it is as accurate as most people need.

[ataradov]

Does anyone know how the frequency measurement works? Is it only for AC voltage with positive and negative swings?

I'm trying to measure frequency on the MCU pin, which is 1 kHz, 0-3.3V, 50% duty cycle. And the meter shows 0.

At the same time if I touch any of the probes, I get 60 Hz (I'm in the US), so it can measure something.

[Lightages]

I can read 90mV P-P no problem at 1kHz on the Hz measurement selection on the dial. On the Hz subselection in ACmV I get a reading at around 50mV P-P.

[ataradov]

So it looks like it needs "hard 0v". With pullups on MCU pins, the logical "0" voltage is actually around 40 mV and this is not enough for frequency measurement.

I've put a battery between the ground lead and the circuit ground to offset the measured voltage and got proper frequency reading on the "Hz" setting. At the same time frequency measurement on AC voltage setting still shows 0.

[Lightages]

Sorry Alex, I didn't answer your question. I was busy doing something else and casually did a test that wasn't very helpful. I just did a test that was actually related to your question!

Yes, it seems that the frequency measurement needs a zero crossing. I was unable to read 0-3.3V with the meter. I was able to read the frequency by putting a 2uF cap in series with the probe. Try a cap of some value and I think you will get your measurement.

[ataradov]

Yes, using a capacitor is an option, but it becomes a hassle. I considered using a meter for quick frequency check to save time on powering up the scope. With the need to look for capacitor, it does not save much time.

[electr_peter]

From video reviews it seems that UT139C beeps whenever rotary dial is turned. Who thought it was a good idea? Is there a way to turn off this annoying beep?
Buttons also beep, right? Is there a way to turn off button beep?

HW mod would help (to disable beep by default) if only there is way to get info about selected continuity mode (to enable beep).

[ataradov]

Yes, it does beep and it is indeed quite annoying. I have no Idea why manufacturers put all those blinky and beepy things all the time, it feels like they don't think their product is good enough without them.

I'd like too see a mod myself.

[electr_peter]

Why do designers think that beeping on any input/activity is a good idea? Do they want do drive us crazy? Turn on -> beep, rotate dial -> beep, press button -> beep, ... At least give an option to disable it.
I would force such designer to use computer keyboard and mouse where any button press leads to old style type writer loud key press sound. That will show them.

Does UT139C turn on/blink back-light on continuity as well as beep? If so, permanently disabling beep would do (almost) no harm for functionality. I have done so with some multimeters which have blink option.

[ataradov]

It definitely does not turn on the back-light, I'm not sure what happens if the back-light is already on, I don't have the meter at hand, but I'm pretty sure it won't do anything special.

[Lightages]

In the case of the back light indicating continuity, no. But if you want to mod the beeper then maybe connecting the back light to the beeper output in some way would be a good substitute. I think needing to look for the back light for continuity indications would be counterproductive.  though.

[Didix]

Gents,

On your web site is mentioned “Optional AC/DC 60A current clamps in different models to measure current up to 60A(1mv=1A)”;
Where can I found the current clamp? Has it a separate ordering code?

Regards!

Uni-T actually don't have anything like that yet in their product line. You should be able to use any generic current clamps that work with multimeter though, such as this: http://www.amazon.com/Tecpel-CA-60-AC-Current-Clamp/dp/B002IRU3IM

Why should I buy a separate $80 clamp when I can get complete clamp meter for $30?
http://www.amazon.com/dp/B005HOPRRK/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=1QZMU23HSUUOC&coliid=I3GLO3CT1DUA92

These words are not meant as a provocation!!

I really would like to know, why one should buy the UT139C plus the referenced clamp  instead of a UT61E plus the UT203?


-Didix

[Lightages]

If you are going to be using a clamp meter it implies that you will be working on high energy circuits. The UT61E is not suited for high energy circuits at all. It does not have proper input protection. The UT139C has much better protection and appears to actually be built correctly for high energy circuits.

Until Uni-T brings out their current clamp for the meter, if they ever do, I would suggest getting a separate clamp meter. The UT211B is pretty good for the money but it is not known if it meets its CAT ratings neither. Good clamp meters tend to cost $200.

[omgfire]

The UT211B is pretty good for the money

Can you explain 3x price difference between UT211B and UT210E?

[electr_peter]

Why should I buy a separate $80 clamp when I can get complete clamp meter for $30?
...
I really would like to know, why one should buy the UT139C plus the referenced clamp  instead of a UT61E plus the UT203?

It depends on what you do and what do you want to achieve. Do you need DMM only for electronics (low power stuff)? Then clamp is useless in any form. Do you need to measure high AC/DC currents? Then you need a clamp.
Clamp with built-in DMM or DMM plus separate clamp adapter - again, it depends. Clamp with built-in DMM has an inconvenient form factor (too massive, too long, too narrow, no stand), but is only one piece instrument.

Price and characteristics wise you have to choose yourself - all depends on requirements.

[edavid]

If you are going to be using a clamp meter it implies that you will be working on high energy circuits.

Why do you say that?  I only use mine on household circuits.

[Didix]

Now I got a UT39C, too.

I thought, the NCV could extend the features of my DMM collection.

However, the reach of the NCV is very moderate. The line needs to be closer than a half inch.
I was not able to detect any line inside my walls (230V).

Somehow disappointing experience ...

-Didix

[ataradov]

I think its primary function is to find out if those uninsulated wires sticking out of the wall will kill you if you want to do something with them, and not finding wires behind the wall.

[SeanB]

Best use of a NCV test is to see if a cable is broken internally, and near which end the break is. You have to be right next to the cable and run down the length, and then it works well.

To detect cabling in walls you are much better off using a stud finder that has a cable detector built in as well, it is a more specialised part more appropriate for this use. I have one, even though most walls here in SA are brick, it does work to tell where the buried conduits are before drilling into a wall to avoid a very nasty surprise.

[Didix]

Ok, good points!

-Didix

[Maxlor]

Can you explain 3x price difference between UT211B and UT210E?

The UT211B is TrueRMs, the UT210E isn't. The UT211B also has a 600mA AC (but not DC) range, which might make it useful as a leakage tester.

From my point of view, as a hobbyist mainly playing with low power DC circuits, the UT210E is far better value for money.

[Lightages]

If you are going to be using a clamp meter it implies that you will be working on high energy circuits.

Why do you say that?  I only use mine on household circuits.

Actually household circuits, if you are referring to house wiring, are considered high energy. If I remember correctly, the distribution panel and any circuits within 10 meters of the panel.

[Lightages]

The UT211B is TrueRMs, the UT210E isn't. The UT211B also has a 600mA AC (but not DC) range, which might make it useful as a leakage tester.

From my point of view, as a hobbyist mainly playing with low power DC circuits, the UT210E is far better value for money.

The UT210E is TRMS. The main differences I see are the current ranges, and the UT210E is 2000 count and the UT211B is 6000 count with slightly better accuracy specifications.