Everyone loves LEDs. I know do. Here’s a pack of 100 assorted LEDs that will last me more than a year and costs less than $2, shipping included.
I like having a supply of cheap, disposable LEDS so I can push them to their limits, and beyond, and not worry about burning one out. I also want them to be good quality so I can leave them in a project.
Many LEDs are incredibly low cost, if you don’t need something really special, like high power, or an exotic color. They are basically a commodity.
I found a source AliExpress.com for 100 assorted red, yellow, green, blue and white LEDs I want to share in this episode. The only downside ordering from AliExpress is it may take 6 weeks to get your shipment.
This is a pack of 100 for $2, or about 2 cents each. Not the cheapest, but still a low cost. Unless I have a project that eats LEDs for breakfast, and I may find such a project, this pack will last me more than a year.
In this pack, it is important to note that the red, yellow and green LEDs and not ultrabrights. This means their forward voltage drop, FVD, is about 2 V. With 20 mA of current, they are bright, but not enough to illuminate a room. They make great indicators, even at 1 mA of current.
The blue and white LEDs are ultra brights. Their FVD is 2.9 V. With 20 mA, they are too bright to stare at directly.
One of the simple experiments you can do with these LEDs is measure the forward voltage drop at a specific current. Using a 5 V source, like from an Arduino, a resistor, like 220 Ohms and two DMMs, we can measure at the same time, the current through the LED and its forward voltage drop. The set up to do this is shown here.
In the example, this green LED has a 2.0 V forward drop at 10 mA current, a very typical value.
