Hello there!

I'm just getting into electronics and I decided to jump in with the 555 ic timer contest. I've been reading the site and all about this stuff for a few months and finally just bought a bunch of shit to get started.

What I'm looking to calculate is the appropriate resistor values in a 555 ic timer circuit that would allow it to be off for 55sec and on for 10sec, repeating as long as there is power (astable mode, ya?). I -really- want it to be ON for 55sec but I've read that it cannot be on for longer than it's off. To compensate I was planning on trying to hook up the output from the 555 to a ground, triggering the unit on when the output was 0.

I found a couple formulas that look like they might be useful for this but I got a little lost--how to I pick the right capacitor value?

t1 = .0693(r1+r2)C

t2 = .0693(r2)C

If my math is right (highly improbable) then 779.22/C=r1. Does this mean I can pick almost any capacitor value and use that to determine the necessary resistor values? Another issue I'm facing here is that I'm not certain of the units of measure in these equations (ohms or mohms? uf or ...?).

Any help is appreciated!