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> Voltmeter Behavior, Verify Accuracy
Superhawk996
post Jun 24 2024, 07:28 PM
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Starting a new thread in response to @emeryGT 350 comment in another thread as follow up

Here’s the background:
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windforfun
post Jun 24 2024, 08:40 PM
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Copy that. The power supply reads out to one place & your DMM reads out to two places.

The DMM is more precise & only more more accurate if it's calibrated.

Precision & accuracy are not the same.

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Superhawk996
post Jun 24 2024, 10:18 PM
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QUOTE(windforfun @ Jun 24 2024, 10:40 PM) *

Copy that. The power supply reads out to one place & your DMM reads out to two places.

The DMM is more precise & only more more accurate if it's calibrated.

Precision & accuracy are not the same.

Yup

Former USAF electronics tech. Fully familiar with using a $3000 (in 1980s dollars) HP bench DMM with resolution to the 4th decimal place with fully traceable calibration to measure a stupid 9v battery.

No need for that type of accuracy or precision for automotive hobby work.

Even working on complicated electronics it was very rare to ever need that level of accuracy and precision. Flukes were disposed of like toilet paper (IMG:style_emoticons/default/sad.gif)

The sad joke was that if you were going to break or lose a piece of test equipment, make sure it was something big and expensive like a $12k O-scope or $30k spectrum analyzer. They can withhold a Fluke out of your check via GPLD if they felt so inclined (Government property Lost or Damaged) but when you made $12k a year; they were never going to recoup something expensive.
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windforfun
post Jun 25 2024, 09:03 AM
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QUOTE(Superhawk996 @ Jun 24 2024, 09:18 PM) *

QUOTE(windforfun @ Jun 24 2024, 10:40 PM) *

Copy that. The power supply reads out to one place & your DMM reads out to two places.

The DMM is more precise & only more more accurate if it's calibrated.

Precision & accuracy are not the same.

Yup

Former USAF electronics tech. Fully familiar with using a $3000 (in 1980s dollars) HP bench DMM with resolution to the 4th decimal place with fully traceable calibration to measure a stupid 9v battery.

No need for that type of accuracy or precision for automotive hobby work.

Even working on complicated electronics it was very rare to ever need that level of accuracy and precision. Flukes were disposed of like toilet paper (IMG:style_emoticons/default/sad.gif)

The sad joke was that if you were going to break or lose a piece of test equipment, make sure it was something big and expensive like a $12k O-scope or $30k spectrum analyzer. They can withhold a Fluke out of your check via GPLD if they felt so inclined (Government property Lost or Damaged) but when you made $12k a year; they were never going to recoup something expensive.


Recognize anything?



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Superhawk996
post Jun 25 2024, 09:33 AM
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QUOTE(windforfun @ Jun 25 2024, 11:03 AM) *



Recognize anything?

@windforfun

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Nice test bench!
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Posts in this topic
Superhawk996   Voltmeter Behavior   Jun 24 2024, 07:28 PM
Superhawk996   I have two gauges, tested both at a variety of vol...   Jun 24 2024, 07:34 PM
Superhawk996   Gauge #1   Jun 24 2024, 07:36 PM
emerygt350   Very interesting! Could you do some readings ...   Jun 24 2024, 07:39 PM
Superhawk996   Yup will do Here’s 14v.   Jun 24 2024, 07:42 PM
Superhawk996   RE: Voltmeter Behavior   Jun 24 2024, 07:46 PM
Superhawk996   Gauge #1 at 13.7v Gauge #2 at full scale - wa...   Jun 24 2024, 07:54 PM
Superhawk996   Gauge #2 12v nominal   Jun 24 2024, 08:09 PM
windforfun   What's the problem? How exactly do you expect...   Jun 24 2024, 08:11 PM
Superhawk996   What's the problem? How exactly do you expec...   Jun 24 2024, 08:20 PM
windforfun   Copy that. The power supply reads out to one plac...   Jun 24 2024, 08:40 PM
Superhawk996   Copy that. The power supply reads out to one pla...   Jun 24 2024, 10:18 PM
windforfun   Copy that. The power supply reads out to one pl...   Jun 25 2024, 09:03 AM
Superhawk996   Recognize anything? @windforfun Nice test ...   Jun 25 2024, 09:33 AM
emerygt350   I was interested in the behavior of the voltage me...   Jun 25 2024, 04:46 AM
mb911   Good data. Unfortunately mine is right on.   Jun 25 2024, 05:17 AM
914Sixer   60's-70's are what I call ball park gauges...   Jun 25 2024, 05:53 AM
emerygt350   I think of it more as a dummy light or perhaps a ...   Jun 25 2024, 06:23 AM
Superhawk996   I should double check my ground shouldn't i...   Jun 25 2024, 06:32 AM
GregAmy   Unless you want to rewire it directly to the batte...   Jun 25 2024, 07:11 AM
emerygt350   Unless you want to rewire it directly to the batt...   Jun 25 2024, 08:44 AM
technicalninja   Thanks, Superhawk! The dash meters are FAR mo...   Jun 25 2024, 08:08 AM
emerygt350   Just checked the grounds engine to body engine to ...   Jun 25 2024, 09:25 AM
Superhawk996   Just checked the grounds engine to body engine to...   Jun 25 2024, 09:29 AM
Superhawk996   gauge #1 Delay and damping behavior related to in...   Jun 25 2024, 09:53 AM
ClayPerrine   For what it is worth, I use the stock voltmeter as...   Jun 25 2024, 10:31 AM
emerygt350   For what it is worth, I use the stock voltmeter a...   Jun 25 2024, 11:17 AM
rjames   emerygt350 might just have a bad gauge. Mine gave ...   Jun 25 2024, 10:47 AM
Superhawk996   emerygt350 might just have a bad gauge. Mine gave...   Jun 25 2024, 11:06 AM
emerygt350   [quote name='rjames' post='3153039' date='Jun 25 ...   Jun 25 2024, 11:20 AM
Superhawk996   [quote name='rjames' post='3153039' date='Jun 25...   Jun 25 2024, 11:24 AM
Superhawk996   Gauge #2 Slightly different damping behavior. P...   Jun 25 2024, 05:18 PM
emerygt350   It is interesting how in both cases they behaved b...   Jun 25 2024, 07:19 PM
Superhawk996   It is interesting how in both cases they behaved ...   Jun 25 2024, 07:54 PM
emerygt350   I finally dug into the console. I had compared th...   Jun 26 2024, 05:02 AM
Superhawk996   :trophy: Now those delays and variable voltage d...   Jun 26 2024, 06:08 AM
emerygt350   :trophy: Now those delays and variable voltage ...   Jun 26 2024, 06:13 AM


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