i am looking for a simple way to have a 555 start up in a high output state and then transistion to astable oscillator after a period of time.

any suggestions?

 

i am looking for a simple way to have a 555 start up in a high output state and then transistion to astable oscillator after a period of time.

any suggestions?

If the delay is not to long you can use a simple RC time constant on the Reset pin. Cap from Reset to GND and Rx to Vcc. When the power is applied the Reset pin is held low until it charges.

 

If the delay is not to long you can use a simple RC time constant on the Reset pin. Cap from Reset to GND and Rx to Vcc. When the power is applied the Reset pin is held low until it charges.

i'll give it a wurl. thanks.

 

If you allow a few parts & a comparator, it will work. Connect 555 as astable, connecting timing resistor to output of comparator. Output of 555 charges a cap. via diode & resistor, forming your initial delay. Cap. + fed to + in to comp., -in to V divider. When comp goes hi, normal timing restored to 555. Holding reset down keeps output lo. When power is applied , timing cap. holds pin 2 lo, output hi.