Just getting back into Arduino and puzzling over this probably basic point.
In my main loop I have an if. Its condition is met and an LED switched on, followed by a delay of 4 seconds, then the end of the if and the loop. But the LED (and its 220 ohm resistor) appears to be getting only about 2.5V. It’s as if it is being switched on and off rapidly. But how can that be happening? Surely the loop should not repeat until the LED goes off?