the top rail is fed by a standard 3v3 regulated power supply
the bottom rail gets 0V or 12V from the external power source. This is what I want to measure (true/false) with my digital pin
the top rail is fed by a standard 3v3 regulated power supply
the bottom rail gets 0V or 12V from the external power source. This is what I want to measure (true/false) with my digital pin