I am a complete novice when it comes to electronics but I am trying to open a transistor when there is audio coming out of my iPod, completing the circuit for my dslr and releasing the shutter.
I have control of the audio so i am outputting a 20hz tone because it has the most voltage somewhere about 1 volt and 5ma AC of course. At the other end my dslr outputs a voltage of 2.7 volts and 0.06ma DC.
I tried this circuit without the capacitor or diode (does the transistor need it?) with a resistor about 2k and a bc548 transistor (only npn one I had) and the signal did trigger a response out of the dslr but it seemed to be interference I guess is coming from the other terminal of the audio line.
Would the capacitor and diode make my circuit work by rectifying the signal and do I need a diode on the other audio source as well.