a light bulb goes on in (one's) head
(redirected from light bulb went on in her head)a light bulb goes on in (one's) head
One is suddenly struck with an ingenious or inspired idea, insight, or revelation. We spent hours trying to come up with a solution, when suddenly a light bulb went on in my head. I kept feeding him subtle hints about the truth of the matter, waiting for a light bulb to go on in his head.
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