Lower resistance is a late addition (9)
I believe the answer is:
decreased
'lower' is the definition.
(thesaurus)
'resistance is a late addition' is the wordplay.
I cannot quite understand how this works, but
'resistance' could be 'r' (electronics abbreviation) and 'r' is present in the answer.
'a' is within the answer.
'late' could be 'dec' (abbreviation for deceased) and 'dec' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for decreased that I've seen before include "Became smaller or fewer" , "Dropped" , "contracted" .)