Andrew Shadow
Site Supporter
Question for the electricians/electronics people.
I have three multi-meters that all give me three different readings on DC voltage output in the 12 to 15 volt DC range. The difference between the three is almost 1 volt, with no two being close enough to matter. This is enough to not allow me to rely on the test results. I can always send them to a calibration lab for testing but I really don't think that it is worth the money. Two of them are fairly decent meters but they are by no means $1,000.00 Fluke meters. Is there something that I can use at home to reliably check their accuracy on DC voltage?
It is easy enough to verify the accuracy of the meters on AC voltage. The voltage from the utility company is very stable and varies very little and is a good reference point. When measuring that AC voltage all three meters are within a few Milli-volts of each other, so fairly trustworthy.
I did the internet search thing and the most common recommendation is to buy a new 1.5 V DC battery and use that as a baseline. The problem with that is that I know from past experience that there can be quite a lot of deviation from 1.5 V DC on new 1.5 V batteries. That variance in conjunction with the variance that I am seeing from the three meters means that I have no idea which one is correct. I was thinking about a cordless tool charger. I have one for an 18V cordless tool. I have never checked the voltage output of one of these chargers so I have no idea how close they normally are to their listed rating or how stable they are, so I wouldn't know which of the three meters is correct anyway. Would this be a reliable DC voltage source for comparison?
I can always compare with someone else's meter, but I won't know if theirs is correct either so not really much help. Any ideas if there is a way that I can confidently check the DC voltage reading on these meters myself?
I have three multi-meters that all give me three different readings on DC voltage output in the 12 to 15 volt DC range. The difference between the three is almost 1 volt, with no two being close enough to matter. This is enough to not allow me to rely on the test results. I can always send them to a calibration lab for testing but I really don't think that it is worth the money. Two of them are fairly decent meters but they are by no means $1,000.00 Fluke meters. Is there something that I can use at home to reliably check their accuracy on DC voltage?
It is easy enough to verify the accuracy of the meters on AC voltage. The voltage from the utility company is very stable and varies very little and is a good reference point. When measuring that AC voltage all three meters are within a few Milli-volts of each other, so fairly trustworthy.
I did the internet search thing and the most common recommendation is to buy a new 1.5 V DC battery and use that as a baseline. The problem with that is that I know from past experience that there can be quite a lot of deviation from 1.5 V DC on new 1.5 V batteries. That variance in conjunction with the variance that I am seeing from the three meters means that I have no idea which one is correct. I was thinking about a cordless tool charger. I have one for an 18V cordless tool. I have never checked the voltage output of one of these chargers so I have no idea how close they normally are to their listed rating or how stable they are, so I wouldn't know which of the three meters is correct anyway. Would this be a reliable DC voltage source for comparison?
I can always compare with someone else's meter, but I won't know if theirs is correct either so not really much help. Any ideas if there is a way that I can confidently check the DC voltage reading on these meters myself?