Simple Test LEDs

Introduction: Simple Test LEDs

About: Jack of All Trades, Master of One: Being Me!
I use LEDs all of the time to quickly test part of a circuit I am building, but fitting an LED and a resistor into a cramped breadboard can be difficult so I combined the two into one!

What You'll Need
  • LEDs - Various Colors
  • 1k ohm resistors - one for each LED
  • Soldering Iron
  • Wire Cutters

The Procedure
  1. Take one of leads of a 1k ohm resistor and wrap it around one of the LED leads a half inch down from the LED - I always put the resistor on the anode of the LED (the longer lead), but the important thing is to be consistent.
  2. Solder the two leads together.
  3. Cut away the excess leads.
Additional Notes
As long as you are consistent as to which lead you solder to (anode or cathode) you will always instantly know which LED lead needs to go to power and which goes to ground.

Another thing you can do with these is add female crimp headers to the lead ends so they can be used on the male header pins of development boards! I make a few with and without.

LED Color
Any color LED will work just fine, but red is the best because red LEDs typically have the lowest voltage requirement to turn on; they are also very easy to see. 

Series Resistance Considerations
I have said to use a 1k ohm resistor, but other values will work just fine. 1k ohm is a good choice because it is safe for almost any application. Refer to the following table for expected LED currents assuming a 2V drop across the LED. All of these current values are safe for the LED, provide visible light, and should be sourced easily from most any device.

VLED  |   R  |   Vcc  |  ILED
  2V        1k      24V      22mA
  2V        1k      12V      10mA
  2V        1k       5V         3mA
  2V        1k      3.3V     1.3mA

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