Circuit Checklist

Before powering on your circuit, make sure that:

• All grounded components are actually grounded (connected to a ground rail on the breadboard that is connected to the GND pin of the Arduino)

• There is no direct connection (by wire or 0-resistance component, such as an LED) between a voltage supply (Arudino output pin) and ground

• The legs of LEDs, resistors, etc are not both plugged in to the same column

  

• You have double-checked that every connection on the circuit diagram matches every connection on the physical circuit (it may help to draw the circuit diagram on a piece of paper and highlight each connection as you check it)

• … Along with that, you have double-checked that the pins you are plugging wires into match the pin numbers on the diagram

• All polarized components, that have an anode and cathode (like LEDs) are wired in the correct direction

• All components are firmly seated in the breadboard