Many times over the years I have wanted to make an adapter from one jack to another. Inevitably I end up wondering if I need to add a resister or capacitor to the usually obvious connections. Can someone explain how I should be thinking about this and how to figure out what discrete component I may or may not need? When I look up information about each end of the connection, all I usually find is an impedance rating for each. (I haven't looked impedances up yet for my example below.)
The current project I have is to be able to plug my (amplified! I'm hearing impaired) cell phone headset (1/8" stereo jack: one conductor for the microphone, one for the mono headphones, and one for ground) into my computer, which takes the (typical) 1/8" stereo jack normally used for stereo speakers and a 1/8" mono jack for a microphone input.
Using the following numbering scheme...
Headset jack: (1) sheath/base = ground, (2) middle conductor = microphone, (3) end conductor = mono headphone. Stereo computer speaker jack: (4) sheath/base = ground, (5) middle conductor = Left speaker, (6) end conductor = Right speaker. Mono computer microphone jack: (7) sheath/base = ground, and (8) end conductor = microphone.
My oversimplistic approach would be to connect (1) to (4) & (7), (2) to (8), and (3) to (5) & (6).
I might have the positive conductors switched on the stereo connections (I haven't checked for which is which), but I think this example makes clear what my simplistic approach is, and may be useful for someone's response. My thoughts always run toward "impedance matching" (whatever that is), but I don't really know enough to run with it from there.
Thanks for any help anyone can give!
Greg