I am trying to measure quite precisely a voltage around 7.2V on a line of a PCB with a voltmeter. In this voltage range, my voltmeter only displays 3 digits. So the reading is something like 7.26V. However, I would like to have 4 digits of resolution.
Idea to solve the problem
To increase the resolution, I connected two voltmeters in series to have the voltage they each measure drop at half the range and benefit from the 4 digit resolutions. When doing so, the first voltmeter is stabilizing at 3.626V. The second one starts its reading, stabilize shortly at 3.626V but soon after restart its reading and repeat this sequence indefinitely.
Is it possible to consider the total voltage to be twice 3.626V, so 7.252V? Is there a risk that the voltmeters are interfering each other in their reading, and I cannot use this result?
How I connected the voltmeter on my circuit.