Conductor travelled to support those chosen (9)
I believe the answer is:
electrode
'conductor' is the definition.
(electrode is a kind of conductor)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for electrode that I've seen before include "Terminal of, eg, an acid battery" , "Conductor for electricity as it enters or leaves" , "Conductor by which current enters" , "Connecting conductor" , "Conductor making contact in a circuit" .)