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Message: <blockquote data-quote="Jakesb" data-source="post: 1180833" data-attributes="member: 13431">Good dayI'm currently converting a Power amp without a trigger input to have a trigger input so that it will turn on/off with an AV amplifier. The trigger output out of the AV amplifier is a continuous 12V when on and no 12V when off. To turn on the power amp I need a relay that will close a contact to turn the amp on or off (placing it in parallel with the power switch of the power amp). So when I receive the 12V signal from the AV amp the relay must briefly close and when the 12V goes away the relay must  close again briefly to turn the power amp off. I found this circuit and bult it: (The 12V pulsed trigger on the output goes to another 12V relay to close the relay contact briefly). I also added flyback diodes to the input relay and the last output relay. Link to the circuit <a href="https://www.remotecentral.com/cgi-bin/mboard/rc-custom/thread.cgi?18902" target="_blank">https://www.remotecentral.com/cgi-bin/mboard/rc-custom/thread.cgi?18902</a>[ATTACH=full]44232[/ATTACH]The circuit worked very well and the power amp turned on and off with the AV amp. After a day I noticed that the power amp turns on and then off immediately when I turn on the AV amp on about 30% of the time. When I turn the AV amp off it always detects the 12V disappearing correctly and it works 100%. The circuit is producing a double trigger somewhere and detecting a quick on/off. Anyone with a better solution to convert 12V falling/rising edge detection into a momentary closed switch? Currently the above mentioned circuit is working 70% of the time. I've seen mentioning of a 555 timer circuit but haven't seen any actual circuits. Arduino is another option but it feels like it would be over-complicating the circuit.</blockquote>

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