Current understanding serves as example (5)
I believe the answer is:
ideal
'example' is the definition.
(I've seen this before)
'current understanding' is the wordplay.
'current' becomes 'I' (symbol for electric current).
'understanding' becomes 'deal' (deal is a kind of understanding).
'i'+'deal'='IDEAL'
'serves as' is the link.
(Other definitions for ideal that I've seen before include "superb specimen" , "'Perfect, model (5)'" , "faultless" , "Ultimate standard of perfection" , "Pattern" .)