Electronic – 555 autostart counting

555delaytimer

In a monostable configuration of the 555:

http://circuitdigest.com/electronic-circuits/555-timer-monostable-circuit-diagram

I have connected pin2 to the ground all the time. My goal is that once the circuit is powered on it starts the counting down right away then turns off after x seconds but this is not what's happening.

The output load will be turned on this way all the time.

How to do it properly then?

Thanks

Best Answer

You need a second R-C to do the triggering.

schematic

simulate this circuit – Schematic created using CircuitLab

Just make sure the R1-C1 time constant is shorter than the R2-C3 time constant — but longer than the rise time of the power supply.