Arduino has shrunk the UNO R4 with the Arduino Nano R4 board equipped with the same 48 MHz Renesas RA4M1 32-bit Arm ...

I do not suggesto to use the Vin pin to power Arduino-Uno with a +5V , as that pin can accept up to +20V, it has an internal recuder to +5v, which uses approximately 2v to stabilize this tension, ...

When working with Arduino boards for the first time, you're bound to make some mistakes, ... But if you're connecting to the VIN pin, take note of the supply's polarity: ...