I'm using a 555 to create a throbbing effect on a LED, like in this project.

Is there a simple way to delay the signal for a second (then third, then forth...) LED to have them fade in and out at different times?

EDIT: I appreciate the workaround suggestions, but I'm really interested in the original question:

Is there a simple way to delay or phase shift the signal?

Even "it's not possible" or "it's very complicated" are good answers.


2 Answers 2


Ok, so that circuit builds the common 555 square wave oscillator and drives an emitter follower from the capacitor voltage. The emitter follower drives the LED.

To get the multi-stage throbing build first a circuit that produces multiple phase-shifted square waves - for example build a ring counter ans drive the clock input using the 555 - then smooth the edges of the pulses from the ring counter with the resistor-capacitor-transistor combination that the throbbing circuit uses. Use a smaller resistor or capacitor on the 555 as it will need to run faster in this application.


I am not sure if this is what you are trying to do, but take a look at 555 based knight rider circuit or 555 based police lights. I don't know what supplies are available, but to add throbbing to these designs you would need multiple 555s or something smarter I can't think of.


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