Then, an Arduino ... analog input pins) now have a special functionality as OPAMP pins, capable of outputting the same voltage or increasing the voltage connected to it. The Uno R4 WiFi Has ...

and an Arduino Uno R3 with an ATmega328P. To do that, he took a bench PSU, added a filter circuit to it, went through the entire ADC range for each board, took a large number of samples at ...