Setting a 555 for 45Hz

[Cobalt60]

So I got the equation:

f = 1 / ( 0.693 x C (R1 + 2 x R2))

I am trying to run a 4017 to run a repeating sequential output to 3 high speed 9V solenoids (15Hz each). So, I am planning on running it off a 555 set at 45Hz.

How do I choose a capacitor? The solenoids were pulled from setups that used 10V 6800uf capacitors, but I assume thats just to drive the solenoids and is separate from the function of the ICs. Also, when choosing resistors, would I try to use as low a value resistor as possible?

Any help greatly appreciated.

-Chris Placzek

 

[mneary]

If this is related to yesterday's 45 Hz 555 thread, it should be continued there.

 

[Cobalt60]

OK im continuing everything related to that thread in that thread, unless otherwise required. For this, I went with a 0.1uF cap, a 10k at R1, and a 200k at R2, to yield 35Hz (a better starting point than 45Hz for this project).

 

[Hero999]

Don't expect a great degree of accuracy, electrolytic capacitors have a typical tolerance of 20% so the frequency could be anywhere between 36Hz and 54Hz before the tolerance of the other components is even considered.