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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.

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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.

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  • \$\begingroup\$ I found the meter drifting a little bit out of spec and I am currently tight on cash. So I have to breathe some new life into this old piece of junk until I can save up enough money to buy a used Keysight 34401A. \$\endgroup\$ – Maxthon Chan Mar 15 '16 at 7:39
  • \$\begingroup\$ How do you know it has drifted out of spec ? \$\endgroup\$ – Bimpelrekkie Mar 15 '16 at 7:40
  • \$\begingroup\$ When I was measuring the output of a brand new MC1403 reference chip the reading was a little bit out of tolerance for the chip. I know my batch of chips should be fine so it is probably my meter being out of spec. \$\endgroup\$ – Maxthon Chan Mar 15 '16 at 7:43
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    \$\begingroup\$ What you could do is measure several of those MC1403 with your old meter, find a sample that is "in the middle" (half the samples have a lower voltage, other half has a higher voltage). That sample should be as close to 2.5 V as you can get. Use that sample to calibrate your meter. \$\endgroup\$ – Bimpelrekkie Mar 15 '16 at 7:48
  • \$\begingroup\$ I decided against calibrating against my batch of MC1403 as I have better graded reference chips ADR02B and ADR03B. Those chips have better initial tolerance specifications that is within the resolution of the meter, so any ADR03B should read 2.50V on my meter. \$\endgroup\$ – Maxthon Chan Mar 15 '16 at 7:50

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