I want to make a multimeter with good precision in measuring resistance mainly, Actually it is not used as a multimeter, I want to measure the resistance of some components in both polarities, It must be capable of reading from 0 ohms to 60 M ohm. And also the main design thing is to inject very less current to the device we are testing since they are very sensitive device. Any Ideas to make it with an Arduino and a display. ??
with good precision in measuring resistance mainly
-What resolution you want? 1 Ohm, 10 Ohm, 100Ohm, 1K Ohm....
-Up to how much error can you accept in the measurement and consider it reliable for your needs? +/-1 Ohm, +/-10 Ohm, +/-100Ohm, +/-1K Ohm.... That is, what accuracy do you need?
-Is 0-60M the actual range the resistance can take? Can it be reduced somehow?
40 Megohms and the OP wants to resolve to within 10 ohms? That's +/- 0.000025% or 0.25 ppm.
The best you can do with the 10 bit ADC of the Arduino with a 40Meg input would be to resolve to 40k ohms. That's an error 4000 times greater than the OP's looking for and that's assuming no error in the measurement!
You need to research a Wheatstone bridge and 4 wire measurement systems to have even half a chance of doing anything useful. Wheatstone bridge - Wikipedia Then you're going to need a good, chopper stabilized micro- or nano- voltmeter.
BTW, the accuracy of the commerical meter the one poster provided a link? They don't even list it! One the 1k ohm range it is +/-0.006%