3.5mm stereo connectors for headphones and microphones are nearly mandatory for audio projects. X1 (left) is a basic plug with connections for the audio channels (pin 2,3), and ground (pin 1). X2 (right) has pass-through contacts (pin 2,3) that divert audio to an internal speaker when headphones aren’t connected.

Here’s a breakdown of the audio connectors illustrated above. We found footprints for these parts, and several other SMD audio connectors, in the con-cuistack part library on the Cadsoft download page.

X1 3.5mm stereo audio jack (Mouser #161-3334-E, $1.16) This is a basic stereo audio jack with no internal pass-through. Fits footprint SJ-3523 in the con-cuistack library.

X2 3.5mm stereo audio jack with internal pass-through (Mouser #161-3335, $1.25) This is our favorite audio jack, but it looks like it’s going to be discontinued soon. Can any individual recommend an equivalent? Fits footprint SJ-3515 in the con-cuistack part library.

Don’t forget to check out our previous parts posts.