Running a 555 timer? Answered
So, I have this program that I got online that simulates a 555-timer. Basically, if you want it to put out X Hz in Astable mode, it'll tell you which capacitors to use and stuff. It'll also show you how you can modify the duty cycle.
I'm wondering if anyone can explain something to me: When I run the program in astable mode, the duty cycle must be above 50%. I want to power an LED that flashes very briefly, but has a relatively large interval of being off until if flashes again. Something more along the lines of a duty cycle of maybe 5%-20%.
First, could you explain why the program constrains the value like this? Is it because the 555 can't run at a duty cycle that isn't greater than 50%? If that is the case, why can't it?
Second, if I can't run it like that, what would you propose I do to power the LED in the manner I described?
btw, if you want the program follow this link: http://clarkson-uk.com/555-timer/
It's actually a pretty cool program! :D