Re: Help with simple 555 timer

The 555 isn't exactly my favourite chip, but I note that you have
omitted the 10nF capacitor from pin 5 to ground that the manufacturers'
data sheets shows on most application circuits,

But usually unnecessary in practice. Its only purpose is to give slightly
greater precision by removing noise pickup.

and you have left the
reset pin (pin 4) open circuit as well - again, in the example circuits
this is returned to the positve rail if the reset function isn't being
used.

THAT's the problem. The 555 will not work unless Reset is connected to V+.
I'm surprised there was any output at all.




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