power to trigger a 555 monostable?

[daviddoria]

ok, i am using an X10 remote power control box to trigger a circuit.

so basically, when the wall power is turned on, it needs to start my 2 second timer. I am using one of those power supplies that takes AC and converts it to 12v DC. so basically, i want to have this 12v from the converted wall AC be on for 2 seconds. how do i do this? won't it destroy my circuit if i just run the 12v to the 555 trigger? i understand how to put a transistor on the output of the 555 with the collector connected to 12v, but how do i trigger it?

thanks
david

 

[Screech]

12 volts is ok.
A simple trigger for a monastable looks like this:

For your aplication, remove the switch and replace it with a transistor.
The transistor is trigered by the same power that the control box Led is powered by.

Thats if you have a Led in your remote control box ,and If I am understanding your question.

 

[Russlk]

Screech's circuit will work, but requires that you push a button. If you want the power on to automaticlly start the timer, replace the push button switch with a .01 uF capacitor.

 

[Screech]

Screech's circuit will work, but requires that you push a button. If you want the power on to automaticlly start the timer, replace the push button switch with a .01 uF capacitor.

I didn't know that Russlk, I must try it out.

 

[JFDuval]

Hi!

12V is ok with a LM/NE555 and maybe some others. Read the datasheet before testing. Somes, like the TLC555, can't take more than 5V.