Products > Test Equipment
Brand new Bm869s calibration
mrdave45:
sorry, i should have specified mV accuracy from 0 to 4.096V range, preferably up to 10V
I would have no need to mV at 1000v range. Usually dealing with tube b+ if its not blown something up then 5% is probably good enough.
bdunham7:
--- Quote from: mrdave45 on February 19, 2021, 06:22:54 pm ---sorry, i should have specified mV accuracy from 0 to 4.096V range, preferably up to 10V
I would have no need to mV at 1000v range. Usually dealing with tube b+ if its not blown something up then 5% is probably good enough.
--- End quote ---
So look at the example above and consider the uncertainty budget. The specs for the 869s on the 50V range are 0.03% of reading + 2 counts, so that comes out to 32 counts if I've mathed rightly. That's +/- 3.2mV, so it won't be quite 'accurate to the mV'. And in real life, the meters here are 23 counts apart, a disagreement of 2.3mV, let alone what the absolute error might be. You should calculate this for yourself on the 5V range and see if that is good enough for you.
joeqsmith:
Looking at a 1V signal off the Fluke standard. Details are important.
Also, just a side comment that may not pertain to you personally. I will get comments from people that will buy the BM869s as their first meter. I think the last one, the person was sending their meter back because when they picked it up with no leads attached the meter would display a voltage. ***They were comparing this where I was showing the Gossen shifting with the input terminated to 50ohms or shorted. *** This wasn't the first beginner who has sent me such a post. I tried it with mind (being winter and dry) and I was able to throw up some numbers that were far worse. I suggested I should perhaps return mine as well.
I like the meter for type of electronics I play with but it may not be the best choice for a beginner. I started out learning the basics with a cheap analog meter which I used for several years. My taste for better equipment came from my hobby evolving. Had someone given me the BM869s when I started out, it would have been a complete waste. You may actually have a need for such a meter.
Video showing my first meter compared with a free one.
joeqsmith:
Fluke standard attached to my old HP, which was used to align the Fluke meter. As I would expect, four meters yields four different answers. I also have no idea what that standard is even good for.
mrdave45:
Ok, it looks as though, if i were to measure a 2.048v level, i would get between 2.0473 and 2.0486. Thats going to be much better than my current meter. Which is only 2000 count, much lower accuracy, and only 2 decimal places in the 20v range. Just looked at the specs, thats 1.5% +4d, I could expect to read between 1.97 and 2.12 or there abouts. In any case, a serious upgrade.
Im not (quite) a beginner. I did a degree in computer systems engineering 20 years ago. Although i followed a career in music, since leaving university I got into building hifi and analogue synthesisers.
Im currently developing a digital control system for an analogue poly synth and Im just finding myself needing to get a better idea of what value the components and voltages Im cobbling together actually is.
Id like a better scope, but that's on hold at the moment. But being able to read voltage and frequency in particular, reasonably accurately will go a long way to help me fine tune and figure whats what. Itll be using substantially less than 1v/oct internally, probably nearer 0.4v/oct which in tern means 33mV per semitone. My current scope and meter just aren't really up to this. I want this to work reasonably well before software correction.
I just haven't bought decent test equipment before and wanted some advice over getting one of these devices stock or whether i should get them calibrated. But having seen the photos of several of these next to higher end bench measurements, I fairly sure this will meet my needs.
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