Great instructional videos, and I watch your videos for hours on end!! Now guess I'm super late, yet just an observation. Prior to changing the batteries your mod power lead was connected to the meter, yet it was not connected when reviewing with fresh batteries. You also noted that even moving the lead was giving fluctuations. IMHO the lead is the culprit here. Keep it up, your hard work is very much appreciated even here in Malta :) I just ordered the 287, thanks to you... Cheers mate.
It's kinda fun watching somebody go through this process; I've been trying to go through it myself lately. It points out that there is SO much to learn about precision measurements and calibration, whether it's electrical, thermal, dimensional, time -- precision measurements and references are HARD! For example, in this video, no consideration of temperature, and not too much meaningful consideration of the tolerances of the references and the measurements. A lot of observation about instability and "settling," but other than the bad power supply, not much of an investigation about what that instabilities really are and where they come from. There are lots of details! Lots and lots of 'em. Ask questions!
@bkupiec Yes...that power supply is really noisy...I play to have a look at it with a scope...I'll also connect a clean DC source to my 287 to see how it behaves then...Thanks again for spotting those bits.
@samgab Interesting...I'm going to check that again when I do the review....I was wondering about taking a delta when the reading settled...will see what that yields...
Open VDC readings that I see are usually charges from your body, if you walk across the floor and touch the body of the meter it will jump. Your F187 is sensitive enough to detect movement in the room on DC after it settles.
A second point, what's usually seen on open VAC readings are usually picked up from the E-field around the mains wiring. Put your meter body near the mains plugs/wiring, you'll see the value rise, also try it on Hz, and you'll see about 50Hz to (60Hz in USA).
A little late, and probably noted already. I believe your problem is that you actually have two voltage sources, which is going to drive something that is looking for reference bonkers. I am curious if you take the batteries out of the meter if you still get the fluctuations. Another point is that the batteries may be taking a charge, which would cause all sorts of strange flows, again driving a voltage reference nuts.
At 2:11 - VAC readings while open. You are seeing 6 VAC, again you meter was plugged in, it should not be that much. My F189 shows about 4mVAC, with only uV fluctuations. So the charger might be affecting VAC readings too. Sounds like it's best not to measure anything while charging to be safe!
It is normal to fluctuate the AC becase it is all around you, power lines in your lab and house are running AC voltage. And why are some fluctuations on DC? AC voltage has also some DC component as you may know, is that fact probably a cause of fluctuations on DC volts?
Your meter leads are acting as antenna and they are picking up some RF voltage.
Great instructional videos, and I watch your videos for hours on end!!
Now guess I'm super late, yet just an observation. Prior to changing the batteries your mod power lead was connected to the meter, yet it was not connected when reviewing with fresh batteries. You also noted that even moving the lead was giving fluctuations. IMHO the lead is the culprit here.
Keep it up, your hard work is very much appreciated even here in Malta :) I just ordered the 287, thanks to you... Cheers mate.
It's kinda fun watching somebody go through this process; I've been trying to go through it myself lately. It points out that there is SO much to learn about precision measurements and calibration, whether it's electrical, thermal, dimensional, time -- precision measurements and references are HARD! For example, in this video, no consideration of temperature, and not too much meaningful consideration of the tolerances of the references and the measurements. A lot of observation about instability and "settling," but other than the bad power supply, not much of an investigation about what that instabilities really are and where they come from. There are lots of details! Lots and lots of 'em. Ask questions!
@bkupiec Yes...that power supply is really noisy...I play to have a look at it with a scope...I'll also connect a clean DC source to my 287 to see how it behaves then...Thanks again for spotting those bits.
Thanks, it may be late but your input is appreciated. Cheers, Martin.
Agree with ForeverMods. It looks like the PSU lead dangling from your 287 is acting as an antenna & picking up stray RF & affecting the meter.
@samgab Interesting...I'm going to check that again when I do the review....I was wondering about taking a delta when the reading settled...will see what that yields...
@electrodacus Yup, good observation...let me see if the scope can throw some light on the matter.
@Shandybrother Not a bad idea....let me see what I can do...
Thanks, appreciate the feedback.
Yup...agreed!
Open VDC readings that I see are usually charges from your body, if you walk across the floor and touch the body of the meter it will jump. Your F187 is sensitive enough to detect movement in the room on DC after it settles.
A second point, what's usually seen on open VAC readings are usually picked up from the E-field around the mains wiring. Put your meter body near the mains plugs/wiring, you'll see the value rise, also try it on Hz, and you'll see about 50Hz to (60Hz in USA).
Hi just wondering if you could do a accuracy test on the DM-620 Multi meter,no one has reviewed it on you tube yet. Thanks i hope you can do this. :-)
A little late, and probably noted already.
I believe your problem is that you actually have two voltage sources, which is going to drive something that is looking for reference bonkers. I am curious if you take the batteries out of the meter if you still get the fluctuations. Another point is that the batteries may be taking a charge, which would cause all sorts of strange flows, again driving a voltage reference nuts.
At 2:11 - VAC readings while open. You are seeing 6 VAC, again you
meter was plugged in, it should not be that much. My F189 shows about
4mVAC, with only uV fluctuations. So the charger might be affecting
VAC readings too. Sounds like it's best not to measure anything while
charging to be safe!
It is normal to fluctuate the AC becase it is all around you, power lines in your lab and house are running AC voltage. And why are some fluctuations on DC? AC voltage has also some DC component as you may know, is that fact probably a cause of fluctuations on DC volts?
Thanks again !
Boa noite