Not sure if that was the right way to ask the question. But, heres what I what I want to do: Using a 9V battey. I would like to light 8, 10, or perhaps more LEDs, not simultaneously but one by one in a sequence. And in asking that, I was going to use a 555 to turn that input signal into a square wave, then perhaps an integrator to make that squarewave spike then dim out. What I am trying to make is a "jar of fireflies" for my daughter. I would build the above circut, maybe two in the same house. So that each LED flares, dims over a moment, goes out, then the next LED starts in sequence. So, is there a IC that does something like that. And secondly, would an integrator (R-C-Ground) work with that DC supply? Thanks in advance for you help and advice.