Battery ?

Yeah, I was pretty impressed myself. I figured the VC99 would be right on the money since it was new… and it was.

I had no Idea the Innova 3320 would be too though, after the treatment it has received… but it was.

And now all my other “cheapos” are right on the money too after I calibrated them. :+1:

The VRM (Voltage Reference Module) is not expensive at all either…. BUT, well worth it’s money for sure.

They are all over ebay. I think mine was around $5. :slight_smile:

[quote=teacher]

Yeah, I’ve got a couple of different voltage reference boards around. Unfortunately, there is no easy way to calibrate my DMM. I can only tell that it’s off a bit.

That’s to bad. I was lucky, even my cheapos had a way to calibrate them.

I had to re-calibrate one 3320 that I had apparently “un-calibrated” a few months ago to a source I though at the time was accurate. :person_facepalming:

Oh well, live and learn. Glad my buddy sent me this VRM though……. :slight_smile:

Is the innova 3320 easy to recalibrate?

Yes, very easy. Loosen 2 screws, remove the back, turn it on, hook up the leads, get your little screw driver and turn the “adjuster thing” very slowly till it reads correct.

I then turn it off & on again, recheck, & if all is still good. … put it back together.

That’s it. :slight_smile:
~
~
EDIT:“adjuster thing” = potentiometer
:wink:

Was it the Uni-t ut61e?

@ teacher It’s good to know how accurate the Innova is and how its been holding up all these years. Its seems like a reliable DMM.

No. I wish it was UT61E, because that one is pretty easy to calibrate.

What I have is Etekcity MSR-U1000 which is a rebranded Uni-T UT61A. This one has multiple potentiometers that could potentially be used for calibration, but so far I have not been able to figure out which one does what and how they interact together, and because the error is pretty small, I decided not to mess with it. Plus, I’m not 100% sure that my voltage reference boards are dead-on accurate either.

FYI, according to my KKMOON rig (based on AD584LH board), the above Etekcity DMM reads low by about 0.22% give or take, so again, not a big deal for me.

Yeah it is Venom, to be honest I was quite pleasantly surprised. :open_mouth:

This one has not been babied at all, I’ve used it on cars, boats, lawn mowers, you name it… plus it has been dropped and mishandled numerous times thru the years. :person_facepalming:

So yes…. I was pleasantly surprised. :wink:

Wow, if I am counting correctly I see five (5) potentiometers. :open_mouth: … :person_facepalming:
You would have to be an electrical engineer to figure that out…… :smiley:

Yup. Someone gave me a link to a technical doc on this DMM, but it was way over my head, so I decided that if it ain’t broke (too badly), don’t fix it. :slight_smile:

Yeah that is pretty small Pete, 6/1000th’s. Close enough for ‘gooberment work’……. :wink:
I like that “case” your VRM is in too……… :+1:
~

Now, if you don’t mind; I have a question for you about you picture below…….

Below the Voltage readout & below where it says “Autorange” there is a group of short vertical lines numbered 0 to 40. It appears as a “horizontal graph” that is reading “38”.

What does that represent or tell you/us

The VC99 is the first DMM I have ever owned that had those.
I have no earthly idea what they represent & if it tells in the “manual”… I can’t find it.
.

Yes, it is certainly within the accuracy range quoted by the manufacturer (+/- 0.5%).

Good question. The owner’s manual does not go into detail about this bar graph. I think it is meant to graphically represent where within the currently chosen measuring range your reading falls. So for example, in that photo, the DMM is in the 4V range, and since the reading is 3.832V, the bar graph illustrates that you are near the upper limit of this range. If your reading was to go above 4V, say 4.1V, the DMM would shift to the next available range (up to 40V), and the bar graph would then illustrate that you are at the lower end of that range.

But those 0, 10, 20, 30, 40 numbers on the bar graph scale are static, regardless of which range you are in, so that is kind of confusing.

Thanks for explaining this. I haven’t really paid attention to how quickly the bar graph updates. I typically check battery voltages with it, where there isn’t much if any rapid fluctuation.

OK, thank you gauss! I appreciate the info and link. :slight_smile:

Here are clickable links to the site gauss referred to. It looks like a ton of good info is there. :slight_smile:

eevblog
Calibration & Standards

Good effort Pete!!! :smiley: Thank you. :+1:

FYI, this is what it looks like…

Your pictures are much better than mine Pete!! :+1: But hopefully it can be seen. On my VC99 the numbers go from 0 to 60.

I am gonna do more reading on the eevblog site gauss linked to and get this figured out in my little ole’ mind. :slight_smile:
……I hope. :wink:

That’s because your DMM is 6,000 count, I presume, which means you get 3 decimal points resolution all the way up to 6V.

In comparison, mine is only 4,000 count. So I only get 3 decimal points resolution up to 4V. Once the measured value is above 4V, mine drops to 2 decimal points, as you can see in the last photo I posted.

BTW, your photos are perfectly fine. :slight_smile:

OH…. OK…… I understand that. :+1:
That is why mine drops to two decimal places on the 7.50 Volt reading. I had been wondering about that.
Thanks for explaining that Pete. :slight_smile:

Very gracious of you Pete……… :wink: …,. Thank you. :slight_smile: