555 timer project help

Thread Starter


Joined Sep 3, 2007
I want to build a circuit that will activate a solid state relay on and off constantly, meaning once the circuit is started the relay will open and close until the crcuit is turned off. I would like to be able to adjust the amount of time the relay opens and closes. I fiqured the best and simplest way would be to use a 555 timer in a constant Astable state. I have checked out a few circuits but I fiqured before I started I would try to get some advice to avoid the pitfalls. The Astable state also alows me to adjust the timing of the 555 timer output waveform. Seems like what I need but maybe someone will have a better idea. Anyways thanks for reading and any help you can give.


Joined Jan 28, 2005
What is your requried cycle rate needed for the relay?

Can you give a few more details about the timing of the circuit?



Joined Apr 20, 2004
It is not acceptable to jump in on another's thread. If you have further questions, please start a new posting to ask it in.

You can get the datasheet for an LM555 timer and use the included formula for the resistor values.