Products > Test Equipment
What's the cheapest 0.02% accuracy handheld meter
bdunham7:
--- Quote from: Fungus on July 16, 2023, 05:12:04 am ---Nope. definitely not like that. That guy's fingers are probably draining the battery faster than the meter.
--- End quote ---
I have really dry hands so that generally isn't a problem. Not that it matters in this case--look more closely at the numbers.
Fungus:
--- Quote from: bdunham7 on July 16, 2023, 05:15:14 am ---
--- Quote from: Fungus on July 16, 2023, 05:12:04 am ---Nope. definitely not like that. That guy's fingers are probably draining the battery faster than the meter.
--- End quote ---
I have really dry hands so that generally isn't a problem. Not that it matters in this case--look more closely at the numbers.
--- End quote ---
Your hand is conducting electricity and warming up the battery? :-//
bdunham7:
--- Quote from: Fungus on July 16, 2023, 05:23:52 am ---Your hand is conducting electricity and warming up the battery? :-//
--- End quote ---
No, neither really. Just to be sure I measured my fingers in the same positions I was holding the battery and with the same probes. With approximately the same pressure used to hold the battery, I'm 106M. With a lot more pressure, 26M. And the battery was cooling down, it had been in a warmer spot.
The whole theme of this thread (to me) is making assumptions without examining them and even resisting challenges to them. The original example was "I want a more accurate (cheap) multimeter and I'm going to judge that solely by the advertised basic DC accuracy headline spec". Now we have drifting battery voltages and assumptions about why that happens.
You see a battery connected to a many-digit multimeter with the LSD slowly counting down. You assume that the reason for that is that the ~150nA is flowing in a 1.5V/10M circuit is drawing down the battery. You see someone doing the same thing but holding the battery in their hand and the voltage is going up, you assume the reason is that the battery temperature is increasing. It turns out that there might be other reasons for these behaviors and unless you somehow quantify the effects that you attribute the changes to, you can't reliably assign causes to your observations.
With an AA battery, unless you can accurately (very accurately) measure temperature and also know how the battery behaves, thermal effects will probably outweigh all those other things by quite a bit. In this case, at near room temperatures, the battery voltage goes down as the battery warms up and there is no discernable difference between the 10M and Hi-Z modes on the meter. If I hold the battery differently so as not to 'short' it with my 100M fingers the voltage changes (drops) more quickly, presumably because more of my hand is in contact with it and thus it warms faster. This is not what I expected when I tried this out just a bit ago.
Things are never as simple as we want them to be.
mwb1100:
Speaking for myself, my comment was just a joke about obsessing over a AA battery measuring 1.456V vs 1.455V. Ie., that I sometimes obsess over absurd things.
Fungus:
--- Quote from: mwb1100 on July 16, 2023, 07:19:46 am ---Speaking for myself, my comment was just a joke about obsessing over a AA battery measuring 1.456V vs 1.455V. Ie., that I sometimes obsess over absurd things.
--- End quote ---
We know :-)
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version