Pin 0 in series with an LED in series with a resistor (380 ohms) and to the ground.
To check if the LED is on, I took the negative lead and draw a wire to pin 1.
Now when the pin 0 is given HIGH, the LED turns on.
Then I digitalRead pin 1 to see if the LED is on, it returns a LOW.
I also checked both ends of LED (while switched on) using pin A0, both sides being at a level “1024”.
Why is the negative end of LED (turned on) give a LOW on digitalRead?