555 as vco

[Hero999]

I suppose, it's impossible to get an exactly 50% duty cycle, there again it's impossible to get anything exact.

 

[Nigel Goodwin]

I suppose, it's impossible to get an exactly 50% duty cycle, there again it's impossible to get anything exact.

Not really, you can adjust it either side of 50%, all you need to do is set it exactly in the middle - the limitation is only in the accuracy of setting it.

 

[mneary]

the limitation is only in the accuracy of setting it.

If you can measure with more resolution than you can adjust, it won't ever look 'exact'.

(1)exhibiting or marked by strict, particular, and complete accordance with fact or a standard

1- Merriam-Webster's online dictionary