Guest
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
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