Vote for excitable doer as conductor (9)
I believe the answer is:
electrode
'conductor' is the definition.
(I know that electrode is a type of conductor)
'vote for excitable doer' is the wordplay.
'vote for' becomes 'elect' (I've seen this in another clue).
'excitable' indicates an anagram (I've seen this in other clues).
'doer' with letters rearranged gives 'rode'.
'elect'+'rode'='ELECTRODE'
'as' is the link.
(Other definitions for electrode that I've seen before include "Conductor making contact in a circuit" , "Conducting contact" , "Conductor (eg, in battery)" , "Conductor by which current enters" , "Connecting conductor" .)