What am I doing wrong (555 timer as a one-shot)?? I'm trying to use a 555 timer to produce a quick pulse whenever a switch is switched a certain way. I have it set up exactly as the data sheet describes (attached picture) and am using a 47 micro Farad Cap as C1 and a 1k ohm resistor. I have the switch connected to "Trigger" (pin 2)...but when I test it out...The pulse is lasting indefinently...and i do mean a long time. it should only be lasting a fraction of a second. I thought it might be a bad IC so I used the other one I had...got the same result. So I got desperate and tied the switch to where Vcc is instead of 5V...it actually worked like a one shot! I know this isn't the correct way to handle an IC...so WHAT could be going on???