how to trigger a relay with audio signal (headphone)?

Want output from headphone jack to power relay to turn on power amp

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Simple clap circuit to detect and amplify an audio signal enough to trigger a transistor latch that will trigger the relay. Google Clap Circuit and Transistor latch for schematics.

gramparich (author)  mpilchfamily2 years ago
Excellent idea EXCEPT :
If I turn off audio, it will not turn off power amp............
I need continuous relay hold until audio goes to zero db.
Thanks for suggestion,
gramps
gramparich (author)  gramparich2 years ago
My first mistake

The use a transistor switch not a latching switch. The point is you want to take the voltage from the Clap circuit's output and use it to turn on a transistor that will activate the relay for you. When the clap looses audio the transistor looses power and the relay flips off again.

gramparich (author)  mpilchfamily2 years ago
Excellent idea
thanks