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| Brand new Bm869s calibration |
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| 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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