Is the function outputs on decoders AC or DC? It is important so I can wire LED headlights.
BB
They are DC. All decoders convert their function outputs to DC because they are using the same rectified current that is used for the motor.
DCC equipped layouts are operating on DC current, with a square-wave AC command signal superimposed over the DC current. The decoder strips the AC command signal out of the current and feeds DC to the motor and function outputs.
I think that is the most comprehensive and succinct explanation I’ve seen yet! Good job, cacole.
What is the polairity of he DC?
BB
The Blue wire is +, the individual function lines (white, yellow, purple, etc) are -.