Realise one's mistake, when switched on? (3,3,5)
I believe the answer is:
see the light
'realise one's mistake' is the definition.
(I've seen this before)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for see the light that I've seen before include "Realise one's mistake" , "Realise the error of one's ways" , "Become converted" , "get it?" , "Gain sudden insight - be religiously converted" .)