On one range, the Arduino charges the capacitor through one resistor and discharges it through another while timing the operation. The amount of time taken corresponds to the capacitance.

This watch using 6 capacitors because they have better dimensions. Board have high effective step up converter with operation to 0.3V, because caps are are charged to 2.5V and then are discharged ...

The meter has a measurement range of 0.1 hertz to 30 hertz for capacitors having values ranging fom 0.47 to 2,200 µF.