Electrical device seen as top performer needing minimal current input (9)
I believe the answer is:
capacitor
'electrical device' is the definition.
(I know that capacitor is a type of electrical device)
'top performer needing minimal current input' is the wordplay.
I cannot really see how this works, but
'top' could be 'tor' and 'tor' is present in the answer.
'current' could be 'ac' (alternating current) and 'ac' is found in the answer.
The remaining letters 'capi' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'seen as' acts as a link.
(Other definitions for capacitor that I've seen before include "Electric charge storer" , "Charge keeper" , "store of electricity" , "Charge-storing device" .)