arduino volt/amp meter

[m3vuv]

Hi all,i am building a new bench psu,i want to build a volt/ampmeter for it using a 16/2 lcd with ic2 interface and a arduino nano,i dont want to use a current sense modual tho,just a current sense resistor,idealt it will have a range from 0-50v and 1ma -20amps any idea where to look for a link etc for this ? TIA.

[rstofer]

If you measure current in the ground side of a device, it's ground voltage obviously increases.  For a light bulb it may not matter, for some kind of logic device it may make a big difference in output voltage to the next device.  If the drop is a low number of millivolts, no problem but, of course, the ADC won't even see the voltage.  You need to work out what size sense resistor will give as many bits of resolution as you require.  Even then, range switching may be required.  You can count on needing gain and an op amp.

For low side measurements:

https://www.instructables.com/DIY-Current-Sensor-for-Arduino/