555 monostable reset problem

Thread Starter


Joined Feb 20, 2007
I have a 555 monostable relay timer. I sometimes fails to turn off at the end of its cycle. It has a reset switch that isn't total necessary for me to have. I could instead wire to #4 reset to #8 pin. Would this solve the issue or is there an easier way?



Joined Mar 31, 2010
Dear Lubby & All
For all those who might find some difficulties with the reset
function i have 2 things to tell you.
Why do think that the 555 in monostable mode is known as "one shot timer"?

Well the reason is that once triggered the 555 from pin2 you cannot deactivate it until the time constant known as RC is passed.
This time constant can be found by using this formula T= C x R x 1.1 .
(Time= Capacitance x Resistance x 1.1)
And yes by connecting the reset pin4 with VCC-pin8 you shouldn't have any problems.
Any way don't just believe my statement confirm yourself by doing some research if you're not so lazy.