パチッ

adverb taking the 'to' particle, noun

with a snap; with a click; with a clack

Describes a sharp, light snapping or clicking sound, like a switch, a lid, or something small breaking.

• スイッチをパチッと入いれた。

  I flipped the switch with a click.

• 枝えだがパチッと折おれた。

adverb taking the 'to' particle, noun

wide-eyed; with a blink; opened wide (of eyes)

Describes eyes opening wide suddenly, often in surprise, or a quick blink. Often used with 目を～させる or 目が～となる.

• 驚おどろいて目めをパチッと見み開ひらいた。

adverb taking the 'to' particle, noun

with a crackle; with a rustle; with a burst

Describes a light crackling or rustling sound, like a small fire, dry leaves, or something bursting open.

• 焚たき火びがパチッと音おとを立たてた。