why pin 7 of 555 not used in this circuit?

[raviram87]

i found this circuit for schmitt trigger using 555 timer...

on simulation, i was able to see the circuit is working fine. But i am not able to understand why pin nyumber 7 of the 555 timer has not been used in the circuit. I tried simulating keeping pin number 7 open, and the circuit is working fine.

I have attached the circuit for reference. Can somebody please explain why pin number 7 is not used here?

 

[ericgibbs]

i found this circuit for schmitt trigger using 555 timer...

on simulation, i was able to see the circuit is working fine. But i am not able to understand why pin nyumber 7 of the 555 timer has not been used in the circuit. I tried simulating keeping pin number 7 open, and the circuit is working fine.

I have attached the circuit for reference. Can somebody please explain why pin number 7 is not used here?

hi,
Its the 'discharge' pin, its not used in this configuration, no timing.

 

[Gayan Soyza]

In monstable operation in 555,

if Vin < 1/3 of supply---> output = high
if Vin > 2/3 of supply---> output = low

if Vin between 1/3 and 2/3 Vs output remains in its present state.