Could somebody please help me. Whenever I try to use a 555 timer chip, the pulse duration is never even close to the calculated value. Oftentimes it is locked at a duration that will not change no matter what values of R or C I use. For example, I just made a monostable multivibrator. I dead bugged it and used a .1uf cap with a 62K resistor. The trigger uses a negative pulse from a shorted out .1uf cap. Pretty standard stuff. I was shooting for about a 7ms pulse to turn on a sensitive gate SCR. The pulse came out at about 12ms. Since the SCR had a turn on time of only 1us, I switched out the resistor to a .1k and left the cap in place. That should have given me about a 10us output pulse but the damn thing is still stuck at 12ms. This is not the first time it has happened to me. I have used different 555's as well as 556's and continue to have these types of problems. What could I possibly be doing to almost never be able to get a simple 555 circuit to work? Is it grounding? Ripple on the power supply? Bypass capacitors? Should I be hooking something to the reset and control pins? I'm at a loss and I could use some guidance.