I have got this circuit working with some of your help and now have a small issue on repeatability.
12v is supplied and the timer module of a mains on off timer is powered with 1.5v. when the timer is set to ON, this then powers up the 555 timer circuit and a receiver board on JP2. pin 4 on JP2 is connected to pin 2 of the 555 timer and starts it. All of this works well.
HOWEVER!!!
when I power on the initial 12v to the 555 sometimes triggers and sets off the sounder circuit. once powered on when I cycle the mains timer module from off, auto and on, when It gets to on, the 555 timer triggers then also. It should only trigger when J2 pin 4 gives it a negative signal.
If I disconnect the timer board...all works well powering on and off so when no load on the 555 timers it all is fine.
Any thoughts.
12v is supplied and the timer module of a mains on off timer is powered with 1.5v. when the timer is set to ON, this then powers up the 555 timer circuit and a receiver board on JP2. pin 4 on JP2 is connected to pin 2 of the 555 timer and starts it. All of this works well.
HOWEVER!!!
when I power on the initial 12v to the 555 sometimes triggers and sets off the sounder circuit. once powered on when I cycle the mains timer module from off, auto and on, when It gets to on, the 555 timer triggers then also. It should only trigger when J2 pin 4 gives it a negative signal.
If I disconnect the timer board...all works well powering on and off so when no load on the 555 timers it all is fine.
Any thoughts.