Multiple Arduino Uno I/O ports driving relay Answered
Understand that the Arduino Uno can output a maximum of 40mA each from its IO port. I used 2 IO ports each (4 in total for switching) to drive a 80mA relay. In this case, the Arduino Uno is powered by USB, which draws up to 500mA. It worked and it was left to switch for a few minutes on pulsed 10 seconds interval. However, the Uno board heats up to around 50-55 degrees centigrade. Will this damage the board?