555 astable problem

Jan 02, 2007 5 Replies

I am trying to set up a cmos 555 as an astable (oscillator). I would like it to output 1 pulse (that is, ON, or high) for 1 second and then stay low for 5-10 seconds before repeating the process again and again. I used to know how to do this, but now I am using the design equations and everything seems to be giving me around a 50% duty cycle. Maybe a



555 is not the right component to use? Any links, advice, or info is greatly appreciated.

TIA, Joe



You might find some of these links useful:

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Good Luck! Rich

Hello Charles,

Yes, thank you so much for that link, I remembered there was a diode involved somewhere. That page even gives the design equations. It's done, I just did the calcs and put the resistors and diode in, and I now have a 1 sec pulse about every 7 seconds. Thank you again.

Joe

Hello Rich,

Well, thank you for the 42,000 links. I am sure I can scare something up in one of them. Just kidding, the previous poster was just a little more specific about where to find the diode trick. I had done the same thing you suggested but was a little discouraged at how many places there are to go to find out about the 555. Hence, my post here.

Joe

You are welcome and Happy New Year (I guess it is still OK to say that).

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