Recommended · for beginners
How to Make a Pulsing/Fading LED Circuit
Why people recommend it
Builds a pulsing, fading LED circuit around a 555 timer; people follow it for small lighting projects and adapt the component values to their own LEDs and supply.
Watch for: component values differ from the commonly linked schematic
In their words
I myself plan on using the following circuit for my tardis project:
Gerben on raspberrypi.stackexchange.com, Jul 2013. CC BY-SA.
I followed the instructions in this video to make a fading LED circuit with a 555 timer:
Pedery on electronics.stackexchange.com, Oct 2016. CC BY-SA.