| Products > Test Equipment |
| Brymen BM789 |
| << < (38/81) > >> |
| bdunham7:
--- Quote from: 2N3055 on September 23, 2021, 06:35:31 pm ---I don't find it interesting if experienced engineers would be surprised by this. Thing that would come to my mind would be more like: they should know better.... --- End quote --- If they hadn't run into it or thought of it, well that's me and a lot of other people. If they don't understand it once tested and explained, that's different. I would have thought that if it was an issue, the DMM manufacturers would take steps to alleviate it--which is completely straightforward and doable-- but apparently they haven't in all cases. You do need a fairly unusual series of steps to make all that happen, so I doubt it is a regular occurrence. |
| Fungus:
Hands on hearts: How many people knew about this and took precautions before reading this thread? |
| floobydust:
After the oscilloscope AC/DC coupling switch went kabang and shot out sparks, I had to think WTF just happened and spend time figuring it out because I couldn't afford to damage precious gear. With ACmV readings, it's the situation where your measurement is out to lunch and you have to dig to find out why. Is the test equipment damaged, or buggy software, used incorrectly, or a misunderstanding about what it can do? A lazy engineer will just sluff it off. |
| joeqsmith:
--- Quote from: Neutrion on September 23, 2021, 03:36:24 pm --- --- Quote from: joeqsmith on September 14, 2021, 11:48:24 pm ---So can I can get the BM789 to read 0 mVAC with a signal applied as I suggested. You bet. Do I care, other than for a small bit of entertainment, not at all. :-DD I could run others but will wait and see what bdunham7 comes up with. --- End quote --- What was the exact waveform here? --- End quote --- I have no way to know exact. From attached, it was roughly a 0.649 VRMS sine with a 2.84VDC bias. --- Quote from: Neutrion on September 23, 2021, 03:36:24 pm ---And regarding the AC coupled mode: Similar to the ipact wrench, or cordless drill tests where they are getting attached to eachother to see which is the stronger, we might see multimeter fights as well in the future! :) --- End quote --- I doubt it as the meters themselves should easily handle it. |
| Neutrion:
--- Quote from: Fungus on September 23, 2021, 08:14:36 pm ---Hands on hearts: How many people knew about this and took precautions before reading this thread? --- End quote --- I had no idea, but than I am also not an experienced engineer. I think with a lots of motors everywhere using inverters, this problem will pose more problems in the future than before. --- Quote from: joeqsmith on September 23, 2021, 09:21:35 pm --- --- Quote from: Neutrion on September 23, 2021, 03:36:24 pm --- --- Quote from: joeqsmith on September 14, 2021, 11:48:24 pm ---So can I can get the BM789 to read 0 mVAC with a signal applied as I suggested. You bet. Do I care, other than for a small bit of entertainment, not at all. :-DD I could run others but will wait and see what bdunham7 comes up with. --- End quote --- What was the exact waveform here? --- End quote --- I have no way to know exact. From attached, it was roughly a 0.649 VRMS sine with a 2.84VDC bias. --- End quote --- Just because the problem is here generally the opposite,(showing something which is much less than it is) so I was wondering whether the sinewave might got too high frequency. Because if not, than it means that the mentioned lowest safety limit could be as low as 0 Volt... Than there is no way of knowing whether because of DC bias an overrange situation occured. With my little offset squarewave, below 400mV AC displayed value one can be on the safe side, but it seems that it is not the case with other waveforms. Like some small AC riding on some DC offset. |
| Navigation |
| Message Index |
| Next page |
| Previous page |