Circuit with two stable states gets protection for lower part (4-4)
I believe the answer is:
flip-flop
'circuit' is the definition.
(I know that Flip-flop is a type of multivibrator)
'two stable states gets protection for lower part' is the wordplay.
I cannot quite see how this works, but
'part' could be 'lip' (lip is a kind of part) and 'lip' is found in the answer.
This explanation may well be incorrect...
'with' is the link.
Can you help me to learn more?
(Other definitions for flip-flop that I've seen before include "Shoe held on by a toe-thong" , "Rubber sandal" , "Flimsy sandal" , "Light shoe" , "Sandal held on by a toe-thong" .)