Errata for the capacitance adapter:
- The PCB template is incorrect. There is a connection between pin 7 of U1 (ground) and the minus connection of the DVM that needs to be cut away. In the template, the trace from pin 7 going down for a few mm and then to the right should only go to the next hole where the strap is soldered. Then it should be cut, and not be allowed to connect to the junction of the parallel capacitors C5 and C7 (whose sum make up 0.2 uF).
Recommendation for the inductance adapter:
- There are sharp pulses in the supply voltage unless a couple of decoupling capacitors are added as in the capacitance adapter. The values are not critical, e. g.: 10 uF/10V on the 9V supply, and 1.5 uF/10 V on the 5V supply.