Principle of the complex integrated circuit (5)
I believe the answer is:
ethic
'principle' is the definition.
(ethic is a kind of principle)
'the complex integrated circuit' is the wordplay.
'complex' indicates an anagram.
'integrated circuit' becomes 'ic' (abbreviation in electronics).
'the' with letters rearranged gives 'eth'.
'eth'+'ic'='ETHIC'
'of' is the link.
(Other definitions for ethic that I've seen before include "Ideology" , "Moral system" , "Moral practice" , "System of principles" , "Set of moral principles" .)