# Electronic – arduino – Using an Arduino to measure wire capacitance

arduinocapacitance

I wanted to use an Arduino as a capacitance measurement device for a coaxial wire. I started at measuring the wire capacitance using digital multi-meter UT58B. I turned the knob to 2 nF and then measured the capacitance depending on the wire length. These are the results: After the measurements I got the function (y = 0.0032x + 0.0268) on how the capacity changes depending on wire length. Now I wanted to use the Arduino to measure the capacitance and then calculate the wire length depending on the capacity. I tried following a guide to make the Arduino be able to measure the capacity.

Now the problem. I tried calculating the needed resistance using R = TC/C for one seond and got:

R = 1/(0.019*10^(-9)) = 52631578947.37 ohm

As you can see the resistance is too big. My questions:

1. Should I decrease the time constant? And how small could it be so that arduino can still measure the time? What maximum resistance can you suggest?

2. Maybe I wrongly read the multi-meter values? (the 2 nF scale)

3. Maybe there are other solutions you can suggest to measuring capacity with Arduino?