I'm experimenting with a bunch of Texas Instruments NE555P IC's that I bought recently from Amazon, I made a basic monostable operation circuit on a breadboard with the following schematics
simulate this circuit – Schematic created using CircuitLab
When I push the button the 555 gets triggered and the LED lights up for few seconds before going off, pushing it again would repeat the process. This is the expected behaviour indeed, however there are two issues I'm experiencing with this circuit.
The first issue is that closing the switch doesnt always trigger the timer, what happens instead is that the LED goes on for only a fracture of a second, I sometimes can overcome this by holding the button down for a second or so and it will then trigger normally after releasing the button.
The second issue is that the trigger duration is larger than \$ 1.1R_{1}C_{1} \$, I tried several different resistance values for \$R_{1}\$ and found out the duration to be about \$1.32R_{1}C_{1}\$ instead (in the circuit above the trigger lasted about 7.40 seconds where it supposted to be 6.16 seconds).
What's causing this erratic behaviour? and why the trigger duration is not consistent with \$1.1R_{1}C_{1}\$?
Last thing I would like to mention is that while testing a 555 IC got zapped (it stopped triggering all together and started heating up), what could have caused that? I used insulated tweezers to avoid ESD damage.