Any electrical people here? got a techy question.

[Guest Will]

2 questions:

Can someone explain what is meant by the term capacitively coupled?

it means that the connection to the jacks for the speakerphone function need this.. (but i don't know what it means).

from the xda developers site:

Audio needs to be capacitively coupled in, any DC bias seems to inhibit audio.

and also can someone point out a circuit to convert car DC to usb useable voltages (ie what is inside those car cigarette lighter>USB devices..?

Any help appreciated..

Will

[Guest fozzie]

Can someone explain what is meant by the term capacitively coupled?

it means that the connection to the jacks for the speakerphone function need this.. (but i don't know what it means).

from the xda developers site:

Audio needs to be capacitively coupled in, any DC bias seems to inhibit audio.

Basically, the audio signal is Alternating Current (AC) whereas a standing voltage would be Direct Current (DC). A capacitor placed in-line will block any DC but will allow AC through. (DC bias means that the AC signal is not centred around 0 volts - the capacitor is used to 'remove' this bias).

I can get more techy if you want but hopefully you get the idea :lol:

[Guest Will]

erm so what size capacitor should i use? sorry everything else in place, but i need to work this bit out..

Will

[Guest kyrkesmith]

Are you trying to make your own cable to go in the headset socket? I had a go at that - without sucess.

[Guest Will]

no i'm using the base connectors, i can get left channel no probs, but mike and right channel are dead.. (muted, not staticy).. and so i want to try this capacitor jobbie.. full diags, and circuits will be provided when done!.

Will