So I am using a 2N2222 Transistor to control a bunch of LEDs. Here is the circuit with an Arduino as the controller:
This works just fine. I set pin 13 to high and the LEDs turn on. I set pin 13 to low and they turn off. Groovy.
Now I want to use a trick. I want to get a flicker/flame effect, so instead of hooking up an expensive Arduino I use a cheap flicker LED as a controller:
This does not work. The main LEDs are always on, even as the flicker LED flickers.
I found that by adding another resistor R I can get it to work:
If R is too big (10k Ohm), then the main LEDs just stay on all the time. If R is too small (100 Ohm), then the LEDs all turn off. If R is 1000 Ohms, then the whole setup works, the three LEDs flicker and I can easily make electric candles/lanterns of any color/size/shape that I want. Cool.
The only thing that bugs me is that I cannot figure out exactly why I need R? Any thoughts?