Resistor LEDs

Make your electronics tinkering experience either more fun or more convenient. Our first half hour hack is the Resistor LED.

A Resistor LED is basically an LED that has had its long leg replaced with an appropriate resistor. This lets you plug it straight into a breadboard without having to find room for a resistor.


To create a Resistor LED you will need:

  • An LED
  • A resistor (330Ω - 560Ω should be fine)
  • A soldering iron
  • Solder
  • Wire cutters
  • Pliers

Before jumping in, test your LED and resistor on a breadboard to make sure that they work together and that the LED works at all - I almost managed to finish a Resistor LED before I realised the LED was dud, whoops!

Making your LED Resistor

To get started, identify the long leg of your LED; this will be the anode. It’s good practise to place the resistor on the long leg for two reasons:

  • It helps you remember which is the anode
  • Circuit designs usually have the resistor before the LED although practically speaking it doesn't make a difference

With your pliers, very carefully pinch one leg of your resistor with the long leg of the LED. Now hold the other end of the resistor and slowly, tightly wrap it around the leg of the LED. You should stop when you have very little slack left over and your resistor is on the inside of the LEDs leg (i.e. between the LEDs two legs).

Now take the other end of the resistor in a pair of pliers and very carefully wrap it around the same leg on the LED. Once finished, use your pliers to tuck the coils at each end neatly together.

You should now have an LED with a resistor hugging its anode. Don’t bridge the resistor from one leg to the other.

Soldering it together

Plug your LED into a breadboard to hold it secure for soldering and get your soldering iron ready. Be careful during this stage, because most LEDs don’t like to be overheated for long. Heat up your iron and dab a little solder on the tip to act as a conductor.

Touch the iron gently against one of the coils, let it heat for a second, and dab the solder directly onto the coil. The solder should melt pretty quickly and be sucked into a neat blob around the coil. Remove the solder and keep holding the iron for a second to make sure this happens.

Do the same for the other end of the resistor.

Now, the astute reader may notice that a resistor soldered in this way will have absolutely no effect on the LED. You’d be right. The LEDs anode is still intact, and will bypass the resistor completely.

The final step is to very, very carefully take your wire cutters and snip away the part of the LED anode which is between the two solder joints. This should leave you with a portion of leg (good and sturdy for plugging into a breadboard) joined by a resistor to the red of the LED anode.

Testing your creation

Now, wire up your new Resistor LED and see if it lights up! If it doesn't check your circuit against a normal resistor and LED and if that works… well you've probably fried the LED. Chalk it up as soldering practise and try again.

Hopefully, though, your resistor LED will work fine! You can now use it for all sorts of things. Try plugging it across the power and ground rails of a breadboard as a power status light, using it as a poor-man’s logic analyser, popping it straight into an Arduino to try your own variation of Blink, or simply plugging several in a row on a 170pt breadboard - where there isn't any room for separate resistors.

The resistor isn't as sturdy as the normal leg of an LED, so be careful when plugging it into a breadboard. I cover mine in a little electrical tape ( I would have used shrink-wrap if I had it to hand ) for a little extra support.