3.5 mm jack internal connections

[at89atbits]

What is the circuitry of a typical 3.5 mm jack supposed to be?



like what is the purpose of each of these pins?

where are these supposed to be connected to?

 

[Audioguru]

The big left part in the schematic of the jack is its barrel. It is the longest part of the plug called the sleeve. It is 0V.
The L terminal (the tip of the plug) is the left stereo channel and the R terminal (the ring of the plug) is the right stereo channel.

A 3.5mm stereo jack can be an input on a computer from an MP3 player, an output to headphones or an output to little speakers.