Electronics > Metrology

16 Bit Multimeter "DIY"

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Since I couldn´t finde the specific topic here I´m going to ask bluntly:
I am currently planning a 4 3/4 Digit multimeter (I know sounds kinda boring compared to others but its a start), and am on the search for a Reference Voltage source that can supply 5.0V, as thats the intended maximum input voltage for the intended ADC, a MAX 195BEPE.
Everything from the Input to the ADC input has been planned and trimmmed for up to 5V input to the ADC.

Thank you in Advance

There are plenty of 5 V reference - which are actually available is another point. The usualy sources often have a search function that includes the in stock point.  For the 4.5 digit range this would likely be a better bandgap type refrence like the max6070, ref5050 or similar.

The ADC is a bit unusual for a DMM, though still possibly. The mormal case would likely include quite some averaging / digital filtering to suppress mains hum.

Well the MAX 195 is just one of the options. I took this one onto my priority list because it its socketed, so i can switch it out. Another spot on the list is the MCP 3427.

If you want the added stability of a buried Zener reference, and don't mind expending more supply current, then you could try an AD586.

EDIT: (You didn't specify handheld or Bench DMM).

Well my plans for the Multimeter are "household" applications i.e. being able to measure 0 to 50V with the 2^16 Steps that a 16Bit ADC can get you.

I don´t know exactly how other DMM´s are constructed but my plan is to have a Input Amp which gives me a 0 to +5V signal (an a polarization signal) for the ADC.
The ADC could then be either a 16bit or something else, depending how accurat i could get the entire ensemble to work.
The Current measurement is planned to be done using a up to 500mV Drop (which compared to the other multimeters I have access to is quite fine) and a .5, 5 or 50 Ohm shunt.
Comparing it to the Multimeter I´m using at work which gets up to 2,5V drop in the 500mA range, i find this pretty harmless.
This is then amplified to the desired 0 to 5V for the ADC via the "depolarizer".
Resistance is measured via a controlled current source (have to work on that one).
The entire device isn´t meant for speed or accuracy, its meant to be functional.

--- Quote --- (You didn't specify handheld or Bench DMM)
--- End quote ---

I am planning for it to be a stationary i.e. bench DMM


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