using a simple voltage divider circuit comprising resistors R1 (100K) and R2 (10K). With the values used in the voltage divider it is possible to feed voltage from 0V to 55V into the Arduino board.

Canadian electronics geek and nascent YouTuber [Technoyaki] wanted to measure 20 volt signals on his Arduino. One might typically use a voltage divider ... build an analog circuit out of sixteen ...