Externet
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Greetings.
Readings of a battery showed 14.4V, 13.9V, 15.5V, 14.7V with four different high impedance 'modern' digital voltmeters for general use (not professional bench instruments).
Probably other scales and measurements are also imprecise.
How to discern which reading - instrument is more reliable as I think cannot be user calibrated -never seen a manual with calibration instructions-
Any way to make/obtain a home-made decent voltage reference ? Would a fresh-new carbon-zinc cell be decent ? What for higher voltage scales ?
How do you and how often check accuracy of your daily use multimeters ?
Checking against a decent oscilloscope falls also to the same uncertainty of such reference being precise. What % of error is reasonable to accept ? Sometimes I charge lithium cells and prefer to avoid errors as their maximum voltage is not very forgiving.
For resistance measurements, perhaps there is a reference kit in the market you prefer to use ? What would you get without breaking the wallet ?
Readings of a battery showed 14.4V, 13.9V, 15.5V, 14.7V with four different high impedance 'modern' digital voltmeters for general use (not professional bench instruments).
Probably other scales and measurements are also imprecise.
How to discern which reading - instrument is more reliable as I think cannot be user calibrated -never seen a manual with calibration instructions-
Any way to make/obtain a home-made decent voltage reference ? Would a fresh-new carbon-zinc cell be decent ? What for higher voltage scales ?
How do you and how often check accuracy of your daily use multimeters ?
Checking against a decent oscilloscope falls also to the same uncertainty of such reference being precise. What % of error is reasonable to accept ? Sometimes I charge lithium cells and prefer to avoid errors as their maximum voltage is not very forgiving.
For resistance measurements, perhaps there is a reference kit in the market you prefer to use ? What would you get without breaking the wallet ?