Light is able to use LED (6)
I believe the answer is:
candle
'light' is the definition.
(candle is a kind of light)
'able to use led' is the wordplay.
'able' becomes 'can'.
'to use' is an anagram indicator.
'led' with letters rearranged gives 'dle'.
'can'+'dle'='CANDLE'
'is' is the link.
(Other definitions for candle that I've seen before include "Old form of illumination" , "may be too expensive for game" , "Maeve Binchy novel 'Light a Penny ......'" , "Wax light source" , "Wax stick with wick" .)