How to Use Solderless Breadboards

Step 3: Add the Resistor

The resistors important in this circuit cause I'm using a 6v power supply and need to bring the voltage down within spec of the LED to between 3.2-3.6v.  If the resistors not in the circuit we risk burning up the LED.

Resistors don't have polarity, so can be oritented either way.  Notice how in the picture above we are connecting into the same row of 5 tie points that the LED's cathode (negative) is hooked into with one of the resistor's leads.  The other resistor lead is then connected to the ground rail (which is then connected to the power source since the entire rail is electrically connected).  That's how we tap into the 6v power supply.

Step 4: Add A Jumper Wire To Finish The Circuit

As it is right now, if you connected the batteries nothing would happen cause the positive power rail is not electrically connected at all to the middle row that the LED's anode lead is connected.  So we could either move the LED's anode to a power rail tie point, or connect a jumper wire from the middle column to the positive rail.

The jumper wire (in purple) is now connecting the middle rows to the postive rail.  So we've completed the full circuit.  With these power rails, you can connect *anywhere* on the rail, but usually it's good to keep the jumper wires as short as possible and tie to the closest tie point on the rail to stay neat.

Next we'll test it out..