I have a hand-me-down multimeter from my Mom made in the 80s. I don't have another meter that is good enough to be used as a calibration standard, however I do have a few reference chips and precision resistors. I hope I can calibrate that multimeter using those.
My 3.5-digit multimeter is a Zhenxing DT-890 made in the 80s. I have a few of each reference chips, ADR02B and ADR03B. I have an And I have a few 0.1% tolerance resistors. Are those reference chips good enough? To calibrate lower voltage ranges, is TLC5615 a good enough chip to use to divide the reference voltage down?
I am on a tight budget so this meter have to be kept in spec for a while, before I can save up for a used Keysight 34401A.
Best Answer
If accuracy is in any way important to you, you will have to spend the money and get a decent multimeter. Depending on how much you want to spend you can get anything between 0.1% and 0.000001% accuracy. What is it worth to you ?
Also ask yourself: what does it bring me if I know this battery is 1.49 V as compared to knowing it's 1.4936 V ? Do you need that accuracy ? If so for what ?
I would forget about trying to calibrate that old multimeter, chances are you will make things worse than they are now. Instead do some tests on it (measure voltage, resistance) and compare the result to that of a know-to-be -accurate meter. If the old meter is in the same ballpark, just use it for the things where you don't need a high accuracy.