Largely upset about tackling spark in restricted circuit (7)
I believe the answer is:
limiter
'restricted circuit' is the definition.
'limiter' can be an answer for 'circuit' (limiter is a kind of circuit). I'm not sure about the 'restricted' bit.
'largely upset about tackling spark' is the wordplay.
'largely' means to remove the last letter.
'upset' becomes 'ill' (similar in meaning).
'about' says the letters should be written backwards.
'tackling spark' becomes 'miter' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'ill' with its last letter taken away is 'il'.
'il' back-to-front is 'li'.
'li'+'miter'='LIMITER'
'in' is the link.
Can you help me to learn more?
(Other definitions for limiter that I've seen before include "Restricting device" , "Something that restricts" , "Controlling device" .)