I was working on a simple monostable IC project and I came acroos this problem.
When the switch is closed which triggers the pin 2 and sets pin 2 on low logic OUTPUT goes HIGH.
As per my settings of C and R it should stay HIGH for nearly 10s. I am using C=82uf and R=120K which gives approx 10s. But, instead OUTPUT is not turning off and it stays HIGH till I disconnect the powersupply.
Here is the schematic.
All grounds are common, and pin 8 is given VCC +5V. I can't figure out the reason. In most all of the circuits I have seen, pin 5 sets capacitor of 10nf. I don't have that a 10nF, so I thought 100pf will work. It may cause some timing malfunction, but I work around that by adjusting the R value. If 10nf is a must and won't work with other than 10nf then please let me know.
Edit: Schematic updated. The 13001s transistor has pin 1 base, pin 2 collector and pin 3 emitter in which pin 3 is connected to gnd, 2 is connected to relay (-) and pin 1 is connected to pin 3 of IC. The relay (+) is connected to pin 4.