555 Timer chip 3 second delay.

Hello, I’m trying to use this guide: http://www.dummies.com/DummiesArticle/E … 10974.html to make 2 LEDs switch on and off. What capacitors/resistors would I need to make the delay 3 seconds? Thanks in advance!

reddot234:
Hello, I’m trying to use this guide: http://www.dummies.com/DummiesArticle/E … 10974.html to make 2 LEDs switch on and off. What capacitors/resistors would I need to make the delay 3 seconds? Thanks in advance!

The duty cycle and period of a 555 timer circuit is well defined and well published on the WWW. Google is your friend. I

even have a 555 application sitting at-the-ready on my desktop. You can too.