Drained power during broadcast (5)
I believe the answer is:
spent
'drained' is the definition.
(I've seen this in another clue)
'power during broadcast' is the wordplay.
'power' becomes 'p'.
'during' is an insertion indicator.
'broadcast' becomes 'sent' (I've seen this in other clues).
'p' put into 'sent' is 'SPENT'.
(Other definitions for spent that I've seen before include "Expended" , "Worn out - after shopping?" , "Burned-out" , "Worn Out, exhausted" , "Worn out, having laid out money" .)