Hi ,
to make it clear: I will not blame the Brymen as a bad meter. It is an excellent meter for this price. I only will point out that very faulty behavior in the AC mV range.
And I do not compare the Brymen with the Gossen, this was only an example for the AC problem. Instead of the Metrahit Energy I can do the same thing with my Benning M7-1, a 170EUR meter, with the same result.
BTW:
The Metrahit Energy has indeed less resolution than the Brymen. But it has the same (or better) accuracy, so the higher Resolution of the Brymen is pretty useless.
And of course the Energy has a capacity measurement as you can see at the pictures.
And as you also can see in the pictures the Fluke 99 is in the manual range. It was only for showing the DC component. The Brymen and the Gossen are in the AC mV range, there is not autorange function in this mode.
Regards
Hello Chronos!
Thank you for a bit of clarification, I better understand what you meant now. And I double checked datasheet, of course you're correct it has capacitance measurement function... My mistake, sorry.
It would be interesting to see what kind of multimeter chipset and differences in schematics Benning has so it measures better.
And I do not say you are wrong with what you see. What I wanted to say it is not error, or some kind of defect. Here on this forum we discuss engineering, so we have to insist on accuracy of statements.
On BM869S mV mode is implemented in such a way that it doesn't decouple input path with capacitor before first stage of amplification. So 500mV range means 500mV of DC, and 500mV AC in combination with it. So instrument is not specified for 10VDC + 10mVAC on mVAC position. That is what it is....
Problem is that BM869S doesn't show Err or Overload when it overloads from that reason....
That IS a problem, and engineering oversight. So you must be careful.
In my checking that range has total dynamic range of +-760mV, roughly 1.5V P-P. If you stay inside that, measurements are perfect.
When I first investigated this, I was confused why it was implemented this way.. It seems that both AC and DC mV switch positions are using AC+DC measurements all the time, just displaying different on display. AC mV is not capacitor decoupled, it is still AC+DC just with AC on primary display.
It certainly does preclude some measurements (like small AC voltages riding on top of large DC offset) directly, but now that I know how it works, I simply can put a capacitor in series with instrument and do it rightly... It is small annoyance, but gives me good results..
If they would change the meter so it does this with proper decoupling I would like that.. It would make meter even better.
Funny thing is that if you measure on DCmV switch position with ACmV in secondary display, it WILL show you DC OVL so you know you are pushing it. So I generally use that most of the time. It will show same ACmV value, it is just on a smaller secondary display. And it shows DC component too if there is any.. So I use it all the time because it gives more information at same time.
I personally think if they improved this ACmV issue, implemented auto hold (measure hold) function and diode testing similar to Fluke (short beep on good diode) that it would be instrument very hard to beat, price regardless..
And accuracy wise, my BM869S is WAAY better than specified on DC specs.. It agrees within 2 last digits with calibrated 6.5 digit DMM.. Also, it is very stable, so increased resolution is actually usable... But I wouldn't claim it better than GOSSEN high end meter.. But as you also agree, it is a small miracle that we can even COMPARE them in same sentence..
Thing is, I don't see need for better handheld than BM869S in my work. If I need better precision and resolution, I measure with my benchtop DMMs.
Thank you for a nice discussion...
All the best,
Sinisa