Works with the circuit (by WEder) based on Arduino nano, see PDF. !!!The ESP32 and the Nano33 iot use 3.3V for any in-/outputs !!! A suggestion for ESP32 pinout is in the PDF. Don't use pins GPIO 0, 6 ...

The Fnirsi LCR-P1 transistor tester can test much more than just transistors. Diodes and passive components are supported, ...