They are designed to operate at 24V. He wanted to use these with common ... and some protection in case something goes wrong with the circuit. Looking at the board above should give you some ...

Over the years, we’ve seen some modern microcontrollers turn out to be 5V-tolerant – now, RP2040 joins the crowd. Half a year ago, when we covered an ISA card based on a Pi Pico, [Eben Upton ...